Science.gov

Sample records for managing radiation degradation

  1. Managing Radiation Degradation of CCDs on the Chandra X-ray Observatory

    NASA Technical Reports Server (NTRS)

    ODell, Stephen L.; Blackwell, William C.; Minow, Joseph I.; Cameron, Robert A.; Morris, David C.; Virani, Shanil N.; Six, N. Frank (Technical Monitor)

    2002-01-01

    The CCDs on the Chandra X ray Observatory are sensitive to radiation damage particularly from low-energy protons scattering off the telescope's mirrors onto the focal plane. In its highly elliptical orbit, Chandra passes through a spatially and temporally varying radiation environment, ranging from the radiation belts to the solar wind. Translating thc Advanced CCD Imaging Spectrometer (ACIS) out of the focal position during radiation-belt passages has prevented loss of scientific utility and eventually functionality. However, carefully managing the radiation damage during the remainder of the orbit, without unnecessarily sacrificing observing time, is essential to optimizing the scientific value of this exceptional observatory throughout its planned 10-year mission. In working toward this optimization, the Chandra team developed aid applied radiation-management strategies. These strategies include autonomous instrument safing triggered by the on-board radiation monitor, as well as monitoring, alerts, and intervention based upon real-time space-environment data from NOAA and NASA spacecraft. Furthermore, because Chandra often spends much of its orbit out of the solar wind (in the Earth's outer magnetosphere and magnetosheath), the team developed the Chandra Radiation Model to describe the complete low-energy-proton environment. Management of the radiation damage has thus far succeeded in limiting degradation of the charge-transfer inefficiency (CTI) to less than 4.4*10^-6 and 1.4*10^-6 per year for the front-illuminated and back-illuminated CCDs, respectively.

  2. Managing radiation degradation of CCDs on the Chandra X-ray Observatory II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldcroft, Thomas L.; Bissell, Bradley A.; Blackwell, William C.; Cameron, Robert A.; Chappell, Jon II.; DePasquale, Joseph M.; Gage, Kenneth R.; Grant, Catherine E.; Harbison, Christine F.

    2005-01-01

    The CCDs on the Chandra X-ray Observatory are vulnerable to radiation damage from low-energy protons scattered off the telescope's mirrors onto the focal plane. Following unexpected damage incurred early in the mission, the Chandra Team developed, implemented, and maintains a radiation-protection program. This program - involving scheduled radiation safing during radiation-belt passes, intervention based upon real-time space-weather conditions and radiation-environment modeling, and on-board radiation monitoring with autonomous radiation safing - has successfully managed the radiation damage to the CCDs. Since implementing the program, the charge-transfer inefficiency (CTI) has increased at an average annual rate of only 2.9x10^-6 (2.3%) for the front- illuminated CCDs and 0.95x10^-6 (6.5%) for the back-illuminated CCDs. This paper describes the current status of Chandra radiation-management program.

  3. Managing Radiation Degradation of CCDs on the Chandra X-Ray Observatory--III

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldcroft, Thomas L.; Blackwell, William C.; Bucher, Sabina L.; Chappell, Jon H.; DePasquale, Joseph M.; Grant, Catherine E.; Juda, Michael; Martin, Eric R.; Minow, Joseph I.; Murray, Stephen S.; Plucinsky, Paul P.; Shropshire, Daniel P.; Spitzbart, Bradley J.; Viens, Paul R.; Wolk, Scott J.; Schwartz, Daniel A.

    2007-01-01

    The CCDs on the Chandra X-ray Observatory are vulnerable to radiation damage from low-energy protons scattered off the telescope's mirrors onto the focal plane. Following unexpected damage incurred early in the mission, the Chandra team developed, implemented, and maintains a radiation-protection program. This program--involving scheduled radiation safing during radiation-belt passes, intervention based upon real-time space-weather conditions and radiation-environment modeling, and on-board radiation monitoring with autonomous radiation safing--has successfully managed the radiation damage to the CCDs. Since implementing the program, the charge-transfer inefficiency (CTI) has increased at an average annual rate of only 3.2x 10(exp -6) (2.3 percent) for the front-illuminated CCDs and 1.0x10(exp -6) (6.7 percent) for the back-illuminated CCDs. This paper describes the current status of the Chandra radiation-management program, emphasizing enhancements implemented since the previous papers.

  4. Radiation degradation of cellulose

    NASA Astrophysics Data System (ADS)

    Leonhardt, J.; Arnold, G.; Baer, M.; Langguth, H.; Gey, M.; Hübert, S.

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment (e.g. radiation influence and influence of lyes) are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20 % up to about 80 %. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given.

  5. Radiation damage calculations for the LANSCE degrader

    SciTech Connect

    Ferguson, P.D.; Sommer, W.F.; Dudziak, D.J.; Wechsler, M.S.; Barnett, M.H.; Corzine, R.K.

    1998-09-01

    The A-6 water degrader at the Los Alamos Neutron Science Center (LANSCE) linear proton accelerator has an outer shell of Inconel 718. The degrader was irradiated by 800-MeV protons during 1988--1993 to an exposure of 5.3 ampere-hours (A h). As described in Ref. 1, material from the Inconel is currently being cut into specimens for microhardness, three-point bending, ball punch, microscopy, and corrosion tests. This paper is devoted to calculations of radiation damage, particularly displacement and He production, sustained by the degrader Inconel.

  6. Radiation Degradation Mechanisms in Laser Diodes

    NASA Technical Reports Server (NTRS)

    Johston, A. H.; Miyahira, T. F.

    2004-01-01

    Degradation mechanisms are investigated for laser diodes fabricated with different materials and wavelengths between 660 and 1550 nm. A new approach is developed that evaluates degradation below the laser threshold to determine the radiation-induced recombination density. This allows mechanisms at high injection, such as Auger recombination, to be separated from low-injection damage. New results show that AlGaInP lasers in the visible region are nearly an order of magnitude more resistant to radiation than devices fabricated with AlGaAs or AlGaAsP at longer wavelengths.

  7. Degradation of cyanobacterial biosignatures by ionizing radiation.

    PubMed

    Dartnell, Lewis R; Storrie-Lombardi, Michael C; Mullineaux, Conrad W; Ruban, Alexander V; Wright, Gary; Griffiths, Andrew D; Muller, Jan-Peter; Ward, John M

    2011-12-01

    Primitive photosynthetic microorganisms, either dormant or dead, may remain today on the martian surface, akin to terrestrial cyanobacteria surviving endolithically in martian analog sites on Earth such as the Antarctic Dry Valleys and the Atacama Desert. Potential markers of martian photoautotrophs include the red edge of chlorophyll reflectance spectra or fluorescence emission from systems of light-harvesting pigments. Such biosignatures, however, would be modified and degraded by long-term exposure to ionizing radiation from the unshielded cosmic ray flux onto the martian surface. In this initial study into this issue, three analytical techniques--absorbance, reflectance, and fluorescence spectroscopy--were employed to determine the progression of the radiolytic destruction of cyanobacteria. The pattern of signal loss for chlorophyll reflection and fluorescence from several biomolecules is characterized and quantified after increasing exposures to ionizing gamma radiation. This allows estimation of the degradation rates of cyanobacterial biosignatures on the martian surface and the identification of promising detectable fluorescent break-down products. PMID:22149884

  8. Radiation-induced degradation of DNA bases

    NASA Astrophysics Data System (ADS)

    Douki, T.; Delatour, T.; Martini, R.; Cadet, J.

    1999-01-01

    Radio-induced degradation of DNA involves radical processes. A series of lesions among the major bases degradation products has been measured in isolated DNA exposed to gamma radiation in aerated aqueous solution. Degradation can be accounted for by the formation of hydroxyl radicals upon radiolysis of water (indirect effect). The four bases are degraded in high yield. Direct effect has been mimicked by photo-induced electron abstraction from the bases producing their radical cation. Quantification of the modified bases showed that guanine is the preferential target. This can be explained by its lower oxidation potential and charge transfer phenomena. La décomposition radio-induite de l'ADN fait intervenir des processus radicalaires. Une série de lésions choisies parmi les produits majeurs de dégradation des bases a été mesurée dans de l'ADN isolé exposé au rayonnement en solution aqueuse aérée. Les modifications sont alors dues aux radicaux hydroxyles produits par la radiolyse de l'eau (effet indirect) et les quatre bases sont efficacement dégradées. L'arrachement d'électrons aux bases par photosensibilisation pour produire leur radical cation, a été utilisé comme modèle de l'effet direct. La quantification des bases modifiées montre que la guanine est préférentiellement dégradée. Cette observation peut s'expliquer par le plus faible potentiel d'oxydation de cette base ainsi que par les phénomènes de transfert de charge vers les guanines.

  9. Remediation and management of degraded lands

    SciTech Connect

    Wong, M.H.; Wong, J.W.C.; Baker, A.J.M.

    1999-11-01

    This book presents the program of the first International Conference on the Remediation and Management of Degraded lands. The book has three sections: mine management and rehabilitation, the management of derelict lands, and soil contamination and reclamation. The 34 chapters present a proactive, solution based approach to the rehabilitation of natural resources. Topics of discussions include the following: the multidisciplinary approach practiced by the Australian Center for Minesite Rehabilitation Research; the relationship between biofuel harvesting and Hong Kong`s continuing upland degradation; and experiments with the effectiveness of EDTA/HCI to remove contaminants from soil.

  10. Aging Management Using Proactive Management of Materials Degradation

    NASA Astrophysics Data System (ADS)

    Doctor, S. R.; Bond, L. J.; Cumblidge, S. E.; Bruemmer, S. M.; Taylor, W. B.; Carpenter, C. E.; Hull, A. B.; Malik, S. N.

    2010-02-01

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors. The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC's Proactive Management of Materials Degradation program and its application to nuclear power plant structures, systems, and components.

  11. AGING MANAGEMENT USING PROACTIVE MANAGEMENT OF MATERIALS DEGRADATION

    SciTech Connect

    Doctor, S. R.; Bond, L. J.; Cumblidge, S. E.; Bruemmer, S. M.; Taylor, W. B.; Carpenter, C. E.; Hull, A. B.; Malik, S. N.

    2010-02-22

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors. The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC's Proactive Management of Materials Degradation program and its application to nuclear power plant structures, systems, and components.

  12. Aging Management using Proactive Management of Materials Degradation

    SciTech Connect

    Doctor, Steven R.; Bond, Leonard J.; Cumblidge, Stephen E.; Bruemmer, Stephen M.; Taylor, W Boyd; Carpenter, C. E.; Hull, Amy B.; Malik, Shah

    2010-10-01

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors (LWRs). The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC’s Proactive Management of Materials Degradation (PMMD) program and its application to nuclear power plant structures, systems, and components (SSC).

  13. Predicting Chandra CCD Degradation with the Chandra Radiation Model

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Blackwell, William C.; DePasquale, Joseph M.; Grant, Catherine E.; O'Dell, Stephen L.; Plucinsky, Paul P.; Schwartz, Daniel A.; Spitzbart, Bradley D.; Wolk, Scott J.

    2008-01-01

    Not long after launch of the Chandra X-Ray Observatory, it was discovered that the Advanced CCD Imaging Spectrometer (ACIS) detector was rapidly degrading due to radiation. Analysis by Chandra personnel showed that this degradation was due to 10w energy protons (100 - 200 keV) that scattered down the optical path onto the focal plane. In response to this unexpected problem, the Chandra Team developed a radiation-protection program that has been used to manage the radiation damage to the CCDs. This program consists of multiple approaches - scheduled sating of the ACIS detector from the radiation environment during passage through radiation belts, real-time monitoring of space weather conditions, on-board monitoring of radiation environment levels, and the creation of a radiation environment model for use in computing proton flux and fluence at energies that damage the ACIS detector. This radiation mitigation program has been very successful. The initial precipitous increase in the CCDs' charge transfer inefficiency (CTI) resulting from proton damage has been slowed dramatically, with the front-illuminated CCDS having an increase in CTI of only 2.3% per year, allowing the ASIS detector's expected lifetime to exceed requirements. This paper concentrates on one aspect of the Chandra radiation mitigation program, the creation of the Chandra Radiation Model (CRM). Because of Chandra's highly elliptical orbit, the spacecraft spends most of its time outside of the trapped radiation belts that present the severest risks to the ACIS detector. However, there is still a proton flux environment that must be accounted for in all parts of Chandra's orbit. At the time of Chandra's launch there was no engineering model of the radiation environment that could be used in the outer regions of the spacecraft's orbit, so the CRM was developed to provide the flux environment of 100 - 200 keV protons in the outer magnetosphere, magnetosheath, and solar wind regions of geospace. This

  14. The degradation of alzak by short wavelength ultraviolet radiation

    NASA Technical Reports Server (NTRS)

    Donohoe, M. J.; Mcintosh, R., Jr.; Henninger, J. H.

    1972-01-01

    The changes in reflectance of thermal aluminum coating samples exposed to different irradiating utraviolet wavelengths are discussed. It is shown that the coating is damaged faster and further by 180 to 210 in radiation than by Lyman alpha radiation. On an equivalent incident energy basis, Lyman alpha does less damage than 180 to 210 nm radiation. Above 300 nm no degradation is observed for long exposures and below 300 nm increasing degradation with decreasing wavelength is found. It is concluded that Lyman alpha radiation need not be included in laboratory testing of this thermal coating for spacecraft structures.

  15. Absorber for terahertz radiation management

    DOEpatents

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  16. Thermal Degradation of Lead Monoxide Filled Polymer Composite Radiation Shields

    SciTech Connect

    Harish, V.; Nagaiah, N.

    2011-07-15

    Lead monoxide filled Isophthalate resin particulate polymer composites were prepared with different filler concentrations and investigated for physical, thermal, mechanical and gamma radiation shielding characteristics. This paper discusses about the thermo gravimetric analysis of the composites done to understand their thermal properties especially the effect of filler concentration on the thermal stability and degradation rate of composites. Pristine polymer exhibits single stage degradation whereas filled composites exhibit two stage degradation processes. Further, the IDT values as well as degradation rates decrease with the increased filler content in the composite.

  17. Radiation-induced degradation of galactomannan polysaccharides

    NASA Astrophysics Data System (ADS)

    Şen, Murat; Yolaçan, Burcu; Güven, Olgun

    2007-12-01

    In this study, guar gum, tara gum and locust bean gum were irradiated in a gamma cell in the solid state. The change in their molecular weights were determined by size exclusion chromatography analysis and the change in their viscosity values with change of temperature and irradiation dose were determined. Chain scission yield, G( s), and degradation rate values were calculated. The calculated G( s) values is 1.09 ± 0.16, 1.07 ± 0.06, 0.85 ± 0.10 for GG, TG and LBG, respectively. The effect of mannose-galactose ratio and initial molecular weight of these gums on the degradation behavior were discussed.

  18. Inhibition of radiation degradation of polyolefins by hydroaromatics

    NASA Astrophysics Data System (ADS)

    Kubo, Junichi; Otsuhata, Kazushige

    Heavy hydroaromatics from petroleum (HHAP) which has evident inhibiting ability toward deterioration of hydrocarbon oils was added to high density polyethylene (PE) and isotactic polypropylene (PP), and the additive effects were examined. After the confirmation of the prominent effects to thermal oxidation of PE and PP, the additive effects to radiation degradation were tested by γ-ray and electron beam irradiations in air. The addition of HHAP was obviously effective in radiation degradation, and the crosslinking of PE was distinctly suppressed by HHAP.

  19. Radiation Degradation of Polytetrafluoroethylene-Lead Composites

    NASA Astrophysics Data System (ADS)

    Karmakar, Sanat; Lawrence, Falix; Mallika, C.; Mudali, U. Kamachi

    2015-11-01

    Composites of polytetrafluoroethylene (PTFE) with Pb (0-15 wt.%) were fabricated and irradiated up to 50 kGy in a 60Co-gamma chamber to evaluate the effect of Pb in improving the radiation tolerance of PTFE. Thermal and mechanical properties were measured for the irradiated and un-irradiated PTFE samples and its composites. The number average molecular weight of PTFE was estimated at different doses from the enthalpy of crystallization values obtained by Differential Scanning Calorimetry. Reduction in the percentage increase in the enthalpy of crystallization and melting of PTFE-15% Pb composite, during irradiation indicated the stabilizing effect of lead on PTFE. Surface morphology of PTFE and its composites revealed that the formation of micro-cracks and blisters in PTFE, owing to radiation damage was controlled by lead. Elongation at break values and SEM images of the irradiated composites indicated that 15% Pb offered better stability to PTFE than 10% Pb.

  20. Radiation-chemical degradation of cellulose and other polysaccharides

    NASA Astrophysics Data System (ADS)

    Ershov, Boris G.

    1998-04-01

    Results of studies on the radiation-chemical transformations of cellulose, its ethers, and some other polysaccharides (xylan, starch, dextran, chitin, chitosan, and heparin) are discussed. Ionising radiation causes the degradation of these compounds accompanied by decomposition of the pyranose ring and formation of compounds with carbonyl and carboxy groups, as well as formation of hydrogen, carbon dioxide, and carbon monoxide. The efficiency of degradation increases considerably with temperature and depends on the structure of the polysaccharide and the nature of its substituents. A mechanism of the radiation-chemical transformations of cellulose and other polysaccharides is suggested. The prospects of using radiation-chemical methods for processing of cellulose and other polysaccharides in industry and agriculture are considered. The bibliography includes 213 references.

  1. Radiation induced inter-device leakage degradation

    NASA Astrophysics Data System (ADS)

    Hu, Zhi-Yuan; Liu, Zhang-Li; Shao, Hua; Zhang, Zheng-Xuan; Ning, Bing-Xu; Chen, Ming; Bi, Da-Wei; Zou, Shi-Chang

    2011-08-01

    The evolution of inter-device leakage current with total ionizing dose in transistors in 180 nm generation technologies is studied with an N-type poly-gate field device (PFD) that uses the shallow trench isolation as an effective gate oxide. The overall radiation response of these structures is determined by the trapped charge in the oxide. The impacts of different bias conditions during irradiation on the inter-device leakage current are studied for the first time in this work, which demonstrates that the worst condition is the same as traditional NMOS transistors. Moreover, the two-dimensional technology computer-aided design simulation is used to understand the bias dependence.

  2. Data acquisition system used in radiation induced electrical degradation experiments

    SciTech Connect

    White, D.P.

    1995-04-01

    Radiation induced electrical degradation (RIED) of ceramic materials has recently been reported and is the topic of much research at the present time. The object of this report is to describe the data acquisition system for an experiment designed to study RIED at the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory.

  3. Curve Fitting Solar Cell Degradation Due to Hard Particle Radiation

    NASA Technical Reports Server (NTRS)

    Gaddy, Edward M.; Cikoski, Rebecca; Mekadenaumporn, Danchai

    2003-01-01

    This paper investigates the suitability of the equation for accurately defining solar cell parameter degradation as a function of hard particle radiation. The paper also provides methods for determining the constants in the equation and compares results from this equation to those obtained by the more traditionally used.

  4. Degradation of chlorophenols in aqueous solution by γ-radiation

    NASA Astrophysics Data System (ADS)

    Hu, Jun; Wang, Jianlong

    2007-08-01

    Degradation of chlorophenols (CPs) in aqueous solutions by γ-radiation was studied. The effect of absorbed dose on degradation, dechlorination and mineralization of CPs were investigated. The results indicated that the degradation of CPs, Cl - release and mineralization increased with increase in absorbed dose. When the initial concentration was 100 mg L -1 and the dosage was 6 kGy, the removal efficiencies of CPs were 44.54% for 2-CP, 91.46% for 3-CP, 82.72% for 4-CP and 93.25% for 2,4-DCP, respectively. The combination of irradiation and H 2O 2 leads to a synergistic effect, which remarkably increased the degradation efficiency of CPs and TOC removal. The kinetics of CPs during irradiation are also mentioned.

  5. Studies of oxidative degradation of polymers induced by ionizing radiation

    SciTech Connect

    Clough, R.L.; Gillen, K.T.

    1989-01-01

    Radiation effects on polymers in the presence of air are characterized by complicated phenomena such as dose-rate effects and post-irradiation degradation. These time-dependent effects can be understood in these terms: (1) features of the free radical chain-reaction chemistry underlying the oxidation, and (2) oxygen diffusion effects. A profiling technique has been developed to study heterogeneous degradation resulting from oxygen diffusion, and kinetic schemes have been developed to allow long-term aging predictions from short-term high dose-rate experiments. Low molecular weight additives which act either as free-radical scavengers or else as energy-scavengers are effective as stabilizers in radiation-oxidation environments. Non-radical oxidation mechanisms, involving species such as ozone, can also be important in the radiation-oxidation of polymers. 18 refs., 15 figs.

  6. Radiation hazards in scoliosis management

    SciTech Connect

    Drummond, D.; Ranallo, F.; Lonstein, J.; Brooks, H.L.; Cameron, J.

    1983-10-01

    Safe radiography in scoliosis management is based on a sound knowledge of 1) the radiographic imaging process, 2) the degree of risk to the patient from radiation exposure, and 3) the radiographic requirements to both evaluate and follow patients with spine deformity. This paper is a current review of the subject and work done at the authors' centers. It includes recommendations for reducing the radiation risk while maintaining necessary diagnostic information.

  7. Petroleum and diesel sulfur degradation under gamma radiation

    NASA Astrophysics Data System (ADS)

    Andrade, Luana dos Santos; Calvo, Wilson Aparecido Parejo; Sato, Ivone Mulako; Duarte, Celina Lopes

    2015-10-01

    Hydrodesulfurization (HDS) is currently the most common method used by refineries to remove sulfur compounds from petroleum fractions. However, it is not highly effective for removing thiophene compounds such as benzothiophene. Additionally, this process generates high costs for the oil industry. In the present work, ionizing radiation was used in order to study the effect on the degradation of petroleum and diesel sulfur compounds. Crude oil and diesel fuel samples were studied, without any pretreatment, and irradiated using a cobalt-60 gamma cell in a batch system at absorbed doses of 30 kGy and 50 kGy. The sulfur compounds were extracted and then analyzed by gas chromatography associated with mass spectrometry (GCMS). A high efficiency of ionizing radiation was observed regarding the degradation of sulfur compounds such as benzothiophene and benzenethiol and the formation of fragments, for example 1.2-dimethylbenzene and toluene.

  8. SMX degradation by ozonation and UV radiation: a kinetic study.

    PubMed

    Liu, Xiaowei; Garoma, Temesgen; Chen, Zhonglin; Wang, Lili; Wu, Youxian

    2012-06-01

    The rate constants of sulfamethoxazole (SMX) degradation by ozonation and UV(254) radiation were investigated under various parameters including influent ozone gas concentration, initial SMX concentration, UV light intensity, ionic strength, water quality in terms of varying anions (bicarbonate, sulfate and nitrate), humic acid (HA) and pH. The results indicated that the removal of SMX by ozonation and UV(254) radiation fitted well to a pseudo first-order kinetic model and the rate constants were in the range of (0.9-9.8)×10(-3) and (1.7-18.9)×10(-3) s(-1), respectively. The second-order rate constants of SMX with ozone (ko(3)), under varying operational parameters, were also determined and varied in the range of (0.60-3.38)±0.13×10(5)M(-1) s(-1). In addition, SMX degradation through UV pretreatment followed by ozonation in the presence of HA was proved to be an effective method which can remove SMX with a low ozone dose. The results suggested that ozonation of SMX was more affected by concentration of influent ozone gas, alkalinity, and HA, while incident UV light intensity, pH, and HA were the dominant factors influencing UV degradation of SMX. PMID:22386457

  9. Radiation induced degradation of pharmaceutical residues in water: Chloramphenicol

    NASA Astrophysics Data System (ADS)

    Csay, Tamás; Rácz, Gergely; Takács, Erzsébet; Wojnárovits, László

    2012-09-01

    The γ-radiolytic degradation of chloramphenicol (CPL) was investigated in 0.1-1 mmol dm-3 aqueous solutions at various radiation conditions. The destruction of CPL was monitored by UV-vis spectrophotometric method through the decrease in the intensity of the absorbance band at 276 nm. LC-MS/MS was used to identify the degradation products. Results indicate that •OH can add onto the CPL aromatic ring or can abstract H-atom from the side chain. The reductive dechlorination of CPL was also studied based on the reaction of eaq- with CPL. In 0.1 mmol dm-3 solution above 2.5 kGy dose complete CPL degradation was achieved. In the presence of dissolved oxygen at relatively low dose, various oxidation products were observed. In the presence of tertiary butanol radical scavenger tertiary butanol group containing products were also detected. The toxicity increased as a function of dose to 1.0 kGy. At doses higher than 1.0 kGy the toxicity decreased continuously due to further degradation. It was also demonstrated that the O2-•/HO2• pair has low reactivity in CPL solution.

  10. Radiation-induced degradation of 4-chloroaniline in aqueous solution

    NASA Astrophysics Data System (ADS)

    Sánchez, M.; Wolfger, H.; Getoff, N.

    2002-12-01

    The radiation-induced decomposition of 4-chloroaniline (4-ClA) was studied under steady-state conditions using aqueous solutions saturated with air, pure oxygen, N 2O, argon and argon in the presence of t-Butanol. Using HPLC-method, the initial G-values of the substrate degradation as well as of a number of radiolytic products were determined. The formation of aminophenols, chlorophenols, aniline and phenol in addition to chloride, ammonia, formaldehyde and mixture of aldehydes as well as carboxylic acids was studied as a function of absorbed dose. Based on the experimental data, probable reaction mechanisms for the degradation of 4-ClA by γ-rays and the formation of the identified products are presented.

  11. Radiation Induced Degradation of Organic Pollutants in Waters and Wastewaters.

    PubMed

    Wojnárovits, László; Takács, Erzsébet

    2016-08-01

    In water treatment by ionizing radiation, and also in other advanced oxidation processes, the main goal is to destroy, or at least to deactivate harmful water contaminants: pharmaceutical compounds, pesticides, surfactants, health-care products, etc. The chemical transformations are mainly initiated by hydroxyl radicals, and the reactions of the formed carbon centered radicals with dissolved oxygen basically determine the rate of oxidation. The concentration of the target compounds is generally very low as compared to the concentration of such natural 'impurities' as chloride and carbonate/bicarbonate ions or the dissolved humic substances (generally referred to as dissolved organic carbon), which consume the majority of the hydroxyl radicals. The different constituents compete for reacting with radicals initiating the degradation. This manuscript discusses the radiation chemistry of this complex system. It includes the reactions of the primary water radiolysis intermediates (hydroxyl radical, hydrated electron/hydrogen atom), the reactions of radicals that form in radical transfer reactions (dichloride-, carbonate- and sulfate radical anions) and also the contribution to the degradation of organic compounds of such additives as hydrogen peroxide, ozone or persulfate. PMID:27573402

  12. Degradation of elastomer by heat and/or radiation

    NASA Astrophysics Data System (ADS)

    Ito, Masayuki

    2007-12-01

    This article studied various problems on the degradation of elastomers by heat and/or radiation. Three kinds of elastomers were irradiated and evaluated by the radiation resistant property using the measurement of tensile test. The fluorine containing elastomer, which has excellent heat resistant properties, was found to be less durable for irradiation than ethylene-propylene-diene (EPDM) elastomer. Ten kinds of different compounding formulas of EPDM were prepared to investigate whether the compounding for heat resistant has durability for irradiation. The thermal exposure was performed in an air oven. The duration of thermal exposure at 140 °C was 384 h. The irradiation condition was 5.0 kGy/h at 70 °C, and the total dose was 0.9 MGy. Elongation retained was taken for the evaluation of the stability. It was found that the formulas for improving the thermal stability did not bring radiation resistant of samples in the experiment. The rate constant of the increase in C dbnd O concentration by heat and radiation was measured and defined as kc( h) and kc( r), respectively. The rate constant of that under the combined addition of the heat and the radiation is expressed as kc( h + r). Eq. (1) was obtained by the experiment and it was found that there is a synergistic relationship between heat and radiation on the increase in C dbnd O concentration kc(h+r)>kc(h)+k(r). Similar relationship was observed on the rate of decrease in ultimate elongation of a certain EPDM.

  13. Radiation degradation in EPICOR-2 ion exchange resins

    SciTech Connect

    McConnell, J.W. Jr.; Johnson, D.A.; Sanders, R.D. Sr.

    1990-09-01

    The Low-Level Waste Data base Development -- EPICOR-II Resin/Liner Investigation Program funded by the US Nuclear Regulatory Commission is investigating chemical and physical conditions for organic ion exchange resins contained in several EPICOR-II prefilters. Those prefilters were used during cleanup of contaminated water from the Three Mile Island Nuclear Power Station after the March 1979 accident. The work was performed by EG G Idaho, Inc. at the Idaho Engineering Laboratory. This is the final report of this task and summarizes results and analyses of three samplings of ion exchange resins from prefilters PF-8 and -20. Results are compared with baseline data from tests performed on unirradiated resins supplied by Epicor, Inc. to determine the extent of degradation due to the high internal radiation dose received by the organic resins. Results also are compared with those of other researchers. 18 refs., 23 figs., 7 tabs.

  14. Radiation induced degradation of xanthan gum in the solid state

    NASA Astrophysics Data System (ADS)

    Şen, Murat; Hayrabolulu, Hande; Taşkın, Pınar; Torun, Murat; Demeter, Maria; Cutrubinis, Mihalis; Güven, Olgun

    2016-07-01

    In this study, the effect of ionizing radiation on xanthan gum was investigated. Xanthan samples were irradiated with gamma rays in air at ambient temperature in the solid state at different dose rates and doses. Change in their molecular weights was followed by size exclusion chromatography (SEC). Chain scission yield (G(S)), and degradation rate constants (k) were calculated. The calculated G(S) values are 0.0151±0.0015, 0.0144±0.0020, 0.0098±0.0010 μmol/J and k values are 1.4×10-8±1.4×10-9, 1.3×10-8±2.0×10-9, 8.7×10-9±1.0×10-9 Gy-1 for 0.1, 3.3 and 7.0 kGy/h dose rates, respectively. It was observed that the dose rate was an important factor controlling the G(S) and degradation rate of xanthan gum. Considering its use in food industry, the effect of irradiation on rheological properties of xanthan gum solutions was also investigated and flow model parameters were determined for all dose rates and doses. Rheological analysis showed that xanthan solution showed non-Newtonian shear thinning behaviour and ionizing radiation does not change the non-Newtonian and shear thinning flow behaviour of xanthan gum solutions in concentration ranges of this work. It was determined that, Power Law model well described the flow behaviour of unirradiated and irradiated xanthan solutions.

  15. Management Practices to Improve Productivity of Degraded/Eroded Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Productivity of degraded/eroded soils can be restored by using organic amendment, such as manure, and improved soil management. A study is being conducted near Hays, KS, to investigate and compare restorative potential of two nitrogen (N) sources. Dried beef manure and urea fertilizer were each appl...

  16. Dose rate effects in radiation degradation of polymer-based cable materials

    NASA Astrophysics Data System (ADS)

    Plaček, V.; Bartoníček, B.; Hnát, V.; Otáhal, B.

    2003-08-01

    Cable ageing under the nuclear power plant (NPP) conditions must be effectively managed to ensure that the required plant safety and reliability are maintained throughout the plant service life. Ionizing radiation is one of the main stressors causing age-related degradation of polymer-based cable materials in air. For a given absorbed dose, radiation-induced damage to a polymer in air environment usually depends on the dose rate of the exposure. In this work, the effect of dose rate on the degradation rate has been studied. Three types of NPP cables (with jacket/insulation combinations PVC/PVC, PVC/PE, XPE/XPE) were irradiated at room temperature using 60Co gamma ray source at average dose rates of 7, 30 and 100 Gy/h with the doses up to 590 kGy. The irradiated samples have been tested for their mechanical properties, thermo-oxidative stability (using differential scanning calorimetry, DSC), and density. In the case of PVC and PE samples, the tested properties have shown evident dose rate effects, while the XPE material has shown no noticeable ones. The values of elongation at break and the thermo-oxidative stability decrease with the advanced degradation, density tends to increase with the absorbed dose. For XPE samples this effect can be partially explained by the increase of crystallinity. It was tested by the DSC determination of the crystalline phase amount.

  17. Management of Spent and Disused Radiation Sources - The Zambian Experience

    SciTech Connect

    Chabala, F.

    2002-02-26

    Zambia like all other countries in the world is faced with environmental problems brought about by a variety of human activities. In Zambia the major environmental issues as identified by Nation Environmental Action Plan (NEAP) of 1994 are water pollution, poor sanitation, land degradation, air pollution, poor waste management, misuse of chemicals, wildlife depletion and deforestation. Zambian has been using a lot of radioactive materials in its various industries. The country has taken several projects with help of external partners. These partners however left these projects in the hands of the Zambians without developing their capacities to manage these radioactive sources. The Government recognized the need to manage these sources and passed legislation governing the management of radioactive materials. The first act of Parliament on Radiation Protection work was passed in 1975 to legislate the use of ionizing radiation. However, because of financial constraints the Country is facing, these regulations have remained unimplemented. Fortunately the international Community has been working in partnership with the Zambian Government in the Management of Radioactive Material. Therefore this paper will present the following aspects of radioactive waste management in Zambia: review Existing Legislation in Zambia regarding management of spent/radioactive sources; capacity building in the field of management of radioactive waste; management of spent and disused radiation sources; existing disposal systems in Zambia regarding spent/orphaned sources; existing stocks of radioactive sources in the Zambian industries.

  18. Workshop Report on Managing Solar Radiation

    NASA Technical Reports Server (NTRS)

    Lane, Lee (Compiler); Caldeira, Ken (Compiler); Chatfield, Robert (Compiler); Langhoff, Stephanie (Compiler)

    2007-01-01

    The basic concept of managing Earth's radiation budget is to reduce the amount of incoming solar radiation absorbed by the Earth so as to counterbalance the heating of the Earth that would otherwise result from the accumulation of greenhouse gases. The workshop did not seek to decide whether or under what circumstances solar radiation management should be deployed or which strategies or technologies might be best, if it were deployed. Rather, the workshop focused on defining what kinds of information might be most valuable in allowing policy makers more knowledgeably to address the various options for solar radiation management.

  19. Proactive Management of Materials Degradation (PMMD) and Enhanced Structural Reliability

    SciTech Connect

    Doctor, Steven R.; Bond, Leonard J.; Cumblidge, Stephen E.; Hull, Amy; Malik, Shah

    2009-09-01

    This paper discusses the U.S. Nuclear Regulatory Commission’s (NRC) activities to further the Proactive Management of Materials Degradation (PMMD), including those to determine the effectiveness of emerging NDE techniques. The paper discusses the first part of the development of a methodology to determine the effectiveness of these emerging NDE techniques for managing metallic degradation. This methodology draws on experience derived from evaluating techniques that have ‘emerged’ in the past. The methodology will follow five stages: a definition of inspection parameters, a technical evaluation, laboratory testing, round-robin testing, and the design of a performance demonstration program. This methodology will document the path taken for previous techniques and set a standardized course for future NDE techniques.

  20. The Fukushima radiation accident: consequences for radiation accident medical management.

    PubMed

    Meineke, Viktor; Dörr, Harald

    2012-08-01

    The March 2011 radiation accident in Fukushima, Japan, is a textbook example of a radiation accident of global significance. In view of the global dimensions of the accident, it is important to consider the lessons learned. In this context, emphasis must be placed on consequences for planning appropriate medical management for radiation accidents including, for example, estimates of necessary human and material resources. The specific characteristics of the radiation accident in Fukushima are thematically divided into five groups: the exceptional environmental influences on the Fukushima radiation accident, particular circumstances of the accident, differences in risk perception, changed psychosocial factors in the age of the Internet and globalization, and the ignorance of the effects of ionizing radiation both among the general public and health care professionals. Conclusions like the need for reviewing international communication, interfacing, and interface definitions will be drawn from the Fukushima radiation accident. PMID:22951483

  1. U.S. Government shutdown degrades aviation radiation monitoring during solar radiation storm

    NASA Astrophysics Data System (ADS)

    Tobiska, W. Kent; Gersey, Brad; Wilkins, Richard; Mertens, Chris; Atwell, William; Bailey, Justin

    2014-01-01

    The U.S. Government shutdown from 1 to 17 October 2013 significantly affected U.S. and global aviation radiation monitoring. The closure occurred just as a S2 radiation storm was in progress with an average dose rate of 20 μSv h-1. We estimate that during the radiation event period, one-half million passengers were flying in the affected zone and, of this population, four would have received sufficient dose to contract fatal cancer in their lifetimes. The radiation environment can be treated like any other risk-prone weather event, e.g., rain, snow, icing, clear air turbulence, convective weather, or volcanic ash, and should be made available to flight crews in a timely way across the entire air traffic management system. The shutdown highlighted the need for active operational monitoring of the global radiation environment. Aviation radiation risk mitigation steps are simple and straightforward, i.e., fly at a lower altitude and/or use a more equatorward route. Public tools and media methods are also needed from the space weather scientific and operational communities to provide this information in a timely and accessible manner to the flying public.

  2. Testing and Qualifying Linear Integrated Circuits for Radiation Degradation in Space

    NASA Technical Reports Server (NTRS)

    Johnston, Allan H.; Rax, Bernard G.

    2006-01-01

    This paper discusses mechanisms and circuit-related factors that affect the degradation of linear integrated circuits from radiation in space. For some circuits there is sufficient degradation to affect performance at total dose levels below 4 krad(Si) because the circuit design techniques require higher gain for the pnp transistors that are the most sensitive to radiation. Qualification methods are recommended that include displacement damage as well as ionization damage.

  3. Meadow degradation, hydrological processes and rangeland management in Tibet

    NASA Astrophysics Data System (ADS)

    He, Siyuan; Richards, Keith

    2013-04-01

    Alpine meadow dominated by species of Kobresia is widely distributed in the Tibetan Plateau. Kobresia pygmaea is often a main species and the meadow has evolved as a result of long-term trampling, being a main rangeland resource for livestock grazing. This alpine meadow also plays an important role in regulating the water and energy balance through land-atmosphere interaction, leaving an impact on local hydrological processes and beyond. Therefore, alpine meadow degradation is detrimental to both the health of the ecosystems, and to pastoralism. This research therefore studies the hydrological process with regard to degradation of Kobresia pygmaea meadow, tracing the possible causes, detecting the impacts on soil and biological properties, and further considering the herders' role in future rangeland management. The study area is around the Kema village of the Nagqu Prefecture in Northern Tibet, where human population depends on livestock grazing for livelihood. Main driving factors of alpine meadow degradation are climatic variations and human disturbance. The periodical change in local climate may be related to quasi-oscillatory atmospheric circulations in this monsoon dominated area and the climatic trends with extreme weather conditions can make the whole system hard to recover. Along with climatic variations, overgrazing is predominant with an exceeding of the carrying capacity by almost every household in this village. This is related to the change of rangeland management by the policies of privatisation of pasture and sedentarisation. The acceleration of degradation since the 1980s results in a series of distinct soil-vegetation combination classified in this research as the normal meadow, compact crust and bare soil. The species composition, soil physical and chemical properties and the vertical water movement along the soil-plant-atmosphere continuum are significantly different at the sites representing stages of degradation, revealed by multiple methods

  4. Improving degradation of paracetamol by integrating gamma radiation and Fenton processes.

    PubMed

    Cruz-González, Germán; Rivas-Ortiz, Iram B; González-Labrada, Katia; Rapado-Paneque, Manuel; Chávez-Ardanza, Armando; Nuevas-Paz, Lauro; Jáuregui-Haza, Ulises J

    2016-10-14

    Degradation of paracetamol (N-(4-hydroxiphenyl)acetamide) in aqueous solution by gamma radiation, gamma radiation/H2O2 and gamma radiation/Fenton processes was studied. Parameters affecting the radiolysis of paracetamol such as radiation dose, initial concentration of pollutant, pH and initial oxidant concentration were investigated. Gamma radiation was performed using a (60)Co source irradiator. Paracetamol degradation and mineralization increased with increasing absorbed radiation dose, but decreased with increasing initial concentration of the drug in aqueous solution. The addition of H2O2 resulted in an increased effect on irradiation-driven paracetamol degradation in comparison with the performance of the irradiation-driven process alone: paracetamol removal increased from 48.9% in the absence of H2O2 to 95.2% for H2O2 concentration of 41.7 mmol/L. However, the best results were obtained with gamma radiation/Fenton process with 100% of the drug removal at 5 kGy, for optimal H2O2 and Fe(2+) concentrations at 13.9 and 2.3 mmol/L, respectively, with a high mineralization of 63.7%. These results suggest gamma radiation/H2O2 and gamma radiation/Fenton processes as promising methods for paracetamol degradation in polluted wastewaters. PMID:27389621

  5. Evaluation of fluorescent dye degradation indirectly induced by x-ray ionizing radiation.

    PubMed

    Benevides, Clayton Augusto; Duarte de Menezes, Frederico; de Araujo, Renato E

    2015-08-01

    This work evaluated the fluorescent dye degradation indirectly induced by ionizing radiation with high energy photons (50 keV). Aqueous gels of agarose with low concentrations of Rhodamine 6G and Fluorescein were submitted to doses of x-ray radiation up to 200 Gy. The dye degradation was analyzed by fluorescence spectroscopy, using an excitation light-emitting diode with a peak wavelength of 462 nm. A rate equation model of fluorophores and radicals' species populations was developed to describe the degradation time behavior of the fluorescent solutions. The model suggests fluorescent dyes should be used in dosimetry. PMID:26368112

  6. Radiation-induced 1/f noise degradation of bipolar linear voltage regulator

    NASA Astrophysics Data System (ADS)

    Qifeng, Zhao; Yiqi, Zhuang; Junlin, Bao; Wei, Hu

    2016-03-01

    Radiation-induced 1/f noise degradation in the LM117 bipolar linear voltage regulator is studied. Based on the radiation-induced degradation mechanism of the output voltage, it is suggested that the band-gap reference subcircuit is the critical component which leads to the 1/f noise degradation of the LM117. The radiation makes the base surface current of the bipolar junction transistors of the band-gap reference subcircuit increase, which leads to an increase in the output 1/f noise of the LM117. Compared to the output voltage, the 1/f noise parameter is more sensitive, it may be used to evaluate the radiation resistance capability of LM117. Project supported by the National Natural Science Foundation of China (Nos. 61076101, 61204092).

  7. Surgical management of radiation enteritis

    SciTech Connect

    Galland, R.B.; Spencer, J.

    1986-02-01

    Seventy patients (17 men and 53 women) were seen with radiation-injured gut between 1958 and 1984. The median age at treatment with radiotherapy was 54 years. External radiotherapy was used in all cases, combined with internal treatment for cervical cancer. Ninety-seven gastrointestinal lesions were produced. There were 63 strictures, 14 fistulas, 12 perforations, and eight bleeds. The period between radiotherapy and clinical manifestation of the lesion was approximately 2 years, being longest for strictures. The majority of the lesions were in the rectosigmoid or mid and distal small bowel. Sixty-one patients required one or more operations, and review of the operative results up to 1977 showed a high incidence of anastomotic leak and death after resection and primary anastomosis. However, we noticed that the ascending, transverse, and descending colon were relatively free of radiation-induced disease. Since then we have used a nonirradiated part of the colon for one end of the anastomosis. Thus terminal ileal resection has been followed by an ileotransverse anastomosis and rectosigmoid resection by mobilization of the splenic flexure to bring it down for anastomosis. With these techniques there has been one leak in 14 anastomoses and none of the 12 patients have died. These results are significantly better (p less than 0.02) than our previous figures when 14 of 27 anastomoses leaked, with 10 deaths. We conclude that use of nonirradiated bowel for at least one end of an anastomosis significantly improves the results of resection of irradiated bowel.

  8. Long-Term Lunar Radiation Degradation Effects on Materials

    NASA Technical Reports Server (NTRS)

    Rojdev, Kristina; ORourke, Mary Jane; Koontz, Steve; Alred, John; Hill, Charles; Devivar, Rodrigo; Morera-Felix, Shakira; Atwell, William; Nutt, Steve; Sabbann, Leslie

    2010-01-01

    The National Aeronautics and Space Administration (NASA) is focused on developing technologies for extending human presence beyond low Earth orbit. These technologies are to advance the state-of-the-art and provide for longer duration missions outside the protection of Earth's magnetosphere. One technology of great interest for large structures is advanced composite materials, due to their weight and cost savings, enhanced radiation protection for the crew, and potential for performance improvements when compared with existing metals. However, these materials have not been characterized for the interplanetary space environment, and particularly the effects of high energy radiation, which is known to cause damage to polymeric materials. Therefore, a study focusing on a lunar habitation element was undertaken to investigate the integrity of potential structural composite materials after exposure to a long-term lunar radiation environment. An overview of the study results are presented, along with a discussion of recommended future work.

  9. Gamma radiation induced degradation in PE-PP block copolymer

    NASA Astrophysics Data System (ADS)

    Ravi, H. R.; Sreepad, H. R.; Ahmed, Khaleel; Govindaiah, T. N.

    2012-06-01

    In the present investigation, effect of gamma irradiation on the PP-PE block copolymer has been studied. The polymer has been subjected to gamma irradiation from 100 to 500 Mrad dosages. Characterization of the polymer using XRD and FTIR was done both before irradiation and after irradiation in each step. Effect of irradiation on the electrical properties of the material has also been studied. FTIR study shows that the sample loses C - C stretching mode of vibration but gains C=C stretching mode of vibration after irradiation. Present investigation clearly indicates that though the electrical conductivity increases in the material, it undergoes degradation and shows brittleness due to irradiation.

  10. Gamma radiation induced degradation in PE-PP block copolymer

    SciTech Connect

    Ravi, H. R.; Sreepad, H. R.; Ahmed, Khaleel; Govindaiah, T. N.

    2012-06-05

    In the present investigation, effect of gamma irradiation on the PP-PE block copolymer has been studied. The polymer has been subjected to gamma irradiation from 100 to 500 Mrad dosages. Characterization of the polymer using XRD and FTIR was done both before irradiation and after irradiation in each step. Effect of irradiation on the electrical properties of the material has also been studied. FTIR study shows that the sample loses C - C stretching mode of vibration but gains C=C stretching mode of vibration after irradiation. Present investigation clearly indicates that though the electrical conductivity increases in the material, it undergoes degradation and shows brittleness due to irradiation.

  11. Comparison of symptomatology and performance degradation for motion and radiation sickness. Technical report, 6 January 1984-31 March 1985

    SciTech Connect

    McClellan, G.E.; Wiker, S.F.

    1985-05-31

    This report quantifies for the first time the relationship between the signs and symptoms of acute radiation sickness and those of motion sickness. With this relationship, a quantitative comparison is made between data on human performance degradation during motion sickness and estimates of performance degradation during radiation sickness. The comparison validates estimates made by the Intermediate Dose Program on the performance degradation from acute radiation sickness.

  12. LIDT test coupled with gamma radiation degraded optics

    NASA Astrophysics Data System (ADS)

    IOAN, M.-R.

    2016-06-01

    A laser can operate in regular but also in nuclear ionizing radiation environments. This paper presents the results of a real time measuring method used to detect the laser induced damage threshold (LIDT) in the optical surfaces/volumes of TEMPAX borosilicate glasses operating in high gamma rays fields. The laser damage quantification technique is applied by using of an automated station intended to measure the damage threshold of optical components, according to the International Standard ISO 21254. Single and multiple pulses laser damage thresholds were determined. For an optical material, life time when it is subjected to multiple pulses of high power laser radiation can be predicted. A few ns pulses shooting laser, operating in regular conditions, inflects damage to a target by its intense electrical component but also in a lower manner by local absorption of its transported thermal energy. When the beam is passing thru optical glass elements affected by ionizing radiation fields, the thermal component is starting to have a more important role, because of the increased thermal absorption in the material's volume caused by the radiation induced color centers. LIDT results on TEMPAX optical glass windows, with the contribution due to the gamma radiation effects (ionization mainly by Compton effect in this case), are presented. This contribution was highlighted and quantified. Energetic, temporal and spatial beam characterizations (according to ISO 11554 standards) and LIDT tests were performed using a high power Nd: YAG laser (1064 nm), before passing the beam through each irradiated glass sample (0 kGy, 1.3 kGy and 21.2 kGy).

  13. Degradation of saturation output of the COTS array charge-coupled devices induced by total dose radiation damage

    NASA Astrophysics Data System (ADS)

    Wang, Zujun; Chen, Wei; Huang, Shaoyan; Liu, Minbo; He, Baoping; Sheng, Jiangkun

    2014-07-01

    Experiments of total dose radiation effects on COTS array charge-coupled device (CCD) and annealing measurements are shown. Degradations of saturation output voltage at different bias conditions are analyzed, and their mechanisms induced by radiation are also demonstrated. Degradations of saturation output imaging at different total doses and the recovery after annealing are also compared. The phenomena of imaging degradation induced by total dose irradiation are analyzed. The camera imaging quality of resolution test card degraded by total dose irradiation is also analyzed. Finally, integration research from the irradiation-sensitive parameter degradation to the camera imaging degradation of the array CCD is achieved.

  14. Effect of G/M ratio on the radiation-induced degradation of sodium alginate

    NASA Astrophysics Data System (ADS)

    Şen, Murat; Rendevski, Stojan; Kavaklı, Pınar Akkaş; Sepehrianazar, Amir

    2010-03-01

    Radiation-induced degradation of sodium alginate (NaAlg) having different G/M ratios was investigated. NaAlg samples were irradiated with gamma rays in air at ambient temperature in the solid state at low dose rate. Change in their molecular weights was followed by size exclusion chromatography (SEC). Changes in their rheological properties and viscosity values as a function of temperature, shear rate and irradiation dose were also determined. Chain scission yields, G( S), and degradation rates were calculated. It was observed that G/M ratio was an important factor controlling the G( S) and degradation rate of sodium alginate.

  15. Product analysis for polyethylene degradation by radiation and thermal ageing

    NASA Astrophysics Data System (ADS)

    Sugimoto, Masaki; Shimada, Akihiko; Kudoh, Hisaaki; Tamura, Kiyotoshi; Seguchi, Tadao

    2013-01-01

    The oxidation products in crosslinked polyethylene for cable insulation formed during thermal and radiation ageing were analyzed by FTIR-ATR. The products were composed of carboxylic acid, carboxylic ester, and carboxylic anhydride for all ageing conditions. The relative yields of carboxylic ester and carboxylic anhydride increased with an increase of temperature for radiation and thermal ageing. The carboxylic acid was the primary oxidation product and the ester and anhydride were secondary products formed by the thermally induced reactions of the carboxylic acids. The carboxylic acid could be produced by chain scission at any temperature followed by the oxidation of the free radicals formed in the polyethylene. The results of the analysis led to formulation of a new oxidation mechanism which was different from the chain reactions via peroxy radicals and peroxides.

  16. Radiation induced degradation of ketoprofen in dilute aqueous solution

    NASA Astrophysics Data System (ADS)

    Illés, Erzsébet; Takács, Erzsébet; Dombi, András; Gajda-Schrantz, Krisztina; Gonter, Katalin; Wojnárovits, László

    2012-09-01

    The intermediates and final products of ketoprofen degradation were investigated in 0.4 mmol dm-3 solution by pulse radiolysis and gamma radiolysis. For observation of final products UV-vis spectrophotometry and HPLC separation with diode array detection were used, and for identification MS was used. The reactions of •OH lead to hydroxycyclohexadienyl type radical intermediates, in their further reactions hydroxylated derivatives of ketoprofen form as final products. The hydrated electron is scavenged by the carbonyl oxygen and the electron adduct protonates to ketyl radical •OH is more effective in decomposing ketoprofen than hydrated electron. Chemical oxygen demand and total organic carbon content measurements on irradiated aerated solutions showed that using irradiation technology ketoprofen can be mineralised. The initial toxicity of the solution monitored by the Daphnia magna test steadily decreases with irradiation. Using 5 kGy dose no toxicity of the solution was detected with this test.

  17. Radiation-induced degradation of cyclohexanebutyric acid in aqueous solutions by gamma ray irradiation

    NASA Astrophysics Data System (ADS)

    Jia, Wenbao; He, Yanquan; Ling, Yongsheng; Hei, Daqian; Shan, Qing; Zhang, Yan; Li, Jiatong

    2015-04-01

    The radiation-induced degradation of cyclohexanebutyric acid under gamma ray irradiation was investigated. Degradation experiments were performed with 100 mL sealed Pyrex glass vessels loaded with 80 mL of cyclohexanebutyric acid solutions at various initial concentrations of 10, 20, and 40 mg L-1. The absorbed doses were controlled at 0, 0.65, 1.95, 3.25, 6.5, 9.75, and 13 kGy. The results showed that gamma ray irradiation could effectively degrade cyclohexanebutyric acid in aqueous solutions. The removal rate of cyclohexanebutyric acid increased significantly with the increase of absorbed dose and the decrease of its initial concentration. At the same time, the removal of chemical oxygen demand (COD) was as effective as that of cyclohexanebutyric acid. The kinetic studies showed that the degradation of cyclohexanebutyric acid followed pseudo first-order reaction. Above all, the proposed mechanism obtained when NaNO2, NaNO3 and tert-butanol were added showed that the •OH radical played a major role in the gamma degradation process of cyclohexanebutyric acid, while •H and eaq- played a minor role in the gamma degradation process. The degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS) during cyclohexanebutyric acid degradation.

  18. Degradation of monoterpenes in orange juice by gamma radiation.

    PubMed

    Fan, X; Gates, R A

    2001-05-01

    Single-strength orange juice was irradiated with 0, 0.89, 2.24, 4.23, and 8.71 gGy of gamma radiation at 5 degrees C and then stored at 7 degrees C for 21 days. Volatile compounds, isolated by solid-phase microextraction, were separated and identified using a gas chromatograph equipped with a mass selective detector. The majority of the volatile compounds were terpenes, and the most abundant volatile compounds were ethanol and limonene. Most volatile compounds were stable during the 21-day storage period except geranial and neral which decreased over time. Irradiation reduced the concentration of acyclic monoterpenes, such as geranial, neral, myrcene, and linalool 1 and 7 days after irradiation, but did not affect other monoterpenes, sesquiterpenes, or other volatile compounds. The reduction of acyclic monterpenes increased linearly with radiation dose, and correlated with an increase in thiobarbituric acid reactive substrates (TBARS) content. Reduction in the concentration of monoterpenes induced by irradiation was not significant 21 days after irradiation. Our results indicate that acyclic monoterpenes are sensitive to irradiation whereas most other volatile compounds are resistant. PMID:11368614

  19. Degradation of radiator performance on Mars due to dust

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Perez-Davis, Marla E.; Rutledge, Sharon K.; Forkapa, Mark

    1992-01-01

    An artificial mineral of the approximate elemental composition of Martian soil was manufactured, crushed, and sorted into four different size ranges. Dust particles from three of these size ranges were applied to arc-textured Nb-1 percent Zr and Cu radiator surfaces to assess their effect on radiator performance. Particles larger than 75 microns did not have sufficient adhesive forces to adhere to the samples at angles greater than about 27 deg. Pre-deposited dust layers were largely removed by clear wind velocities greater than 40 m/s, or by dust-laden wind velocities as low as 25 m/s. Smaller dust grains were more difficult to remove. Abrasion was found to be significant only in high velocity winds (89 m/s or greater). Dust-laden winds were found to be more abrasive than clear wind. Initially dusted samples abraded less than initially clear samples in dust laden wind. Smaller dust particles of the simulant proved to be more abrasive than large. This probably indicates that the larger particles were in fact agglomerates.

  20. Management of radiation-induced urethral strictures

    PubMed Central

    Hofer, Matthias D.

    2015-01-01

    Radiation as a treatment option for prostate cancer has been chosen by many patients. One of the side effects encountered are radiation-induced urethral strictures which occur in up to 11% of patients. Radiation damage has often left the irradiated field fibrotic and with poor vascularization which make these strictures a challenging entity to treat. The mainstay of urologic management remains an urethroplasty procedure for which several approaches exist with variable optimal indication. Excision and primary anastomoses are ideal for shorter bulbar strictures that comprise the majority of radiation-induced urethral strictures. One advantage of this technique is that it does not require tissue transfers and success rates of 70-95% have consistently been reported. Substitution urethroplasty using remote graft tissue such as buccal mucosa are indicated if the length of the stricture precludes a tension-free primary anastomosis. Despite the challenge of graft survival in radiation-damaged and poorly vascularized recipient tissue, up to 83% of patients have been treated successfully although the numbers described in the literature are small. The most extensive repairs involve the use of tissue flaps, for example gracilis muscle, which may be required if the involved periurethral tissue is unable to provide sufficient vascular support for a post-operative urethral healing process. In summary, radiation-induced urethral strictures are a challenging entity. Most strictures are amenable to excision and primary anastomosis (EPA) with encouraging success rates but substitution urethroplasty may be indicated when extensive repair is needed. PMID:26816812

  1. Energy loss process analysis for radiation degradation and immediate recovery of amorphous silicon alloy solar cells

    NASA Astrophysics Data System (ADS)

    Sato, Shin-ichiro; Beernink, Kevin; Ohshima, Takeshi

    2015-06-01

    Performance degradation of a-Si/a-SiGe/a-SiGe triple-junction solar cells due to irradiation of silicon ions, electrons, and protons are investigated using an in-situ current-voltage measurement system. The performance recovery immediately after irradiation is also investigated. Significant recovery is always observed independent of radiation species and temperature. It is shown that the characteristic time, which is obtained by analyzing the short-circuit current annealing behavior, is an important parameter for practical applications in space. In addition, the radiation degradation mechanism is discussed by analyzing the energy loss process of incident particles (ionizing energy loss: IEL, and non-ionizing energy loss: NIEL) and their relative damage factors. It is determined that ionizing dose is the primarily parameter for electron degradation whereas displacement damage dose is the primarily parameter for proton degradation. This is because the ratio of NIEL to IEL in the case of electrons is small enough to be ignored the damage due to NIEL although the defect creation ratio of NIEL is much larger than that of IEL in the cases of both protons and electrons. The impact of “radiation quality effect” has to be considered to understand the degradation due to Si ion irradiation.

  2. Radiation Induced Degradation of White Thermal Control Paint

    NASA Technical Reports Server (NTRS)

    Edwards, D. L.; Zwiener, J. M.; Wertz, G. E.; Vaughn, Jason A.; Kamenetzky, Rachel R.; Finckenor, M. M.; Meshishnek, M. J.

    1999-01-01

    This paper details a comparison analysis of the zinc-oxide pigmented white thermal control paints Z-93 and Z-93P. Both paints were simultaneously exposed to combined space environmental effects and analyzed using an in-vacuo reflectance technique. The dose applied to the paints was approximately equivalent to 5 yr in a geosynchronous orbit. This comparison analysis showed that Z-93P is an acceptable substitute for Z-93. Irradiated samples of Z-93 and Z-93P were subjected to additional exposures of ultraviolet (UV) radiation and analyzed using the in-vacuo reflectance technique to investigate UV activated reflectance recovery. Both samples showed minimal UV activated reflectance recovery after an additional 190 equivalent Sun hour (ESH) exposure. Reflectance response utilizing nitrogen as a repressurizing gas instead of air was also investigated. This investigation found the rates of reflectance recovery when repressurized with nitrogen are slower than when repressurized with air.

  3. Radiation Induced Degradation of White Thermal Control Paint

    NASA Technical Reports Server (NTRS)

    Edwards, D. L.; Zwiener, J. M.; Wertz, G. E.; Vaughn, J. A.; Kamenetzky, R. R.; Finckenor, M. M.; Meshishnek, M. J.

    1998-01-01

    This paper details a comparison analysis of the Zinc Oxide pigmented white thermal control paints Z-93 and Z-93P. Both paints were simultaneously exposed to combined space environmental effects and analyzed using an in-vacuum reflectance technique. The dose applied to the paints was approximately equivalent to 5 years in a geosynchronous orbit. This comparison analysis showed that Z-93P is an acceptable substitute for Z-93. Irradiated samples of Z-93 and Z-93P were subjected to additional exposures of ultraviolet (UV) radiation and analyzed using the in-vacuum reflectance technique to investigate UV activated reflectance recovery. Both samples showed minimal UV activated reflectanc6 recovery after an additional 190 Equivalent Sun Hour (ESH) exposure. Reflectance response utilizing nitrogen as a repressurizing gas instead of air was also investigated. This investigation found the rates of reflectance recovery when repressurized with nitrogen are slower than when repressurized with air.

  4. Radiation Induced Degradation of White Thermal Control Paint

    NASA Technical Reports Server (NTRS)

    Edwards, D. L.; Zwiener, J. M.; Wertz, G. E.; Vaughn, Jason A.; Kamenetzky, Rachel R.; Finckenor, M. M.; Meshishnek, M. J.

    1998-01-01

    This paper details a comparison analysis of the zinc-oxide pigmented white thermal control paints Z-93 and Z-93P. Both paints were simultaneously exposed to combined space environmental effects and analyzed using an in-vacuo reflectance technique. The dose applied to the paints was approximately equivalent to 5 yr in a geosynchronous orbit. This comparison analysis showed that Z-93P is an acceptable substitute for Z-93. Irradiated samples of Z-93 and Z-93P were subjected to additional exposures of ultraviolet (UV) radiation and analyzed using the in-vacuo reflectance technique to investigate UV activated reflectance recovery. Both samples showed minimal UV activated reflectance recovery after an additional 190 equivalent Sun hour (ESH) exposure. Reflectance response utilizing nitrogen as a repressurizing gas instead of air was also investigated. This investigation found the rates of reflectance recovery when repressurized with nitrogen are slower than when repressurized with air.

  5. Degradation of thermal shield materials in the space radiation environment

    NASA Astrophysics Data System (ADS)

    Shimoji, S.; Kimura, H.; Koitabashi, M.; Imamura, T.; Kasai, R.; Matsushita, M.

    1983-12-01

    Changes in temperature distribution data of Experimental Technology Satellite 4 after its 3 months mission term are discussed. Analysis of the data suggested that the thermal shields loose their function in the space radiation environment. The effect of energetic particles on the shield materials was investigated. Electron beams of 500 keV and proton beams of 900 keV were irradiated on silver-Teflon and aluminized Kapton films. The fluences were changed between 10 to the 14th and 10 to the 16th power sqcm. Temperature varied between -100 and 100C. Solar absorptance, infrared emittance, tensile strength and elongation rate were measured. Thermogravimetry, infrared spectroscopy and X-ray diffraction were performed. Electron fluxes have remarkable effects on the mechanical properties, proton fluxes on the thermophysical properties of silver-Teflon film. Kapton films do not change much.

  6. Proactive Management of Materials Degradation for Nuclear Power Plant Systems

    SciTech Connect

    Bond, Leonard J.; Taylor, Theodore T.; Doctor, Steven R.; Hull, Amy; Malik, Shah

    2008-09-01

    There are approximately 440 operating reactors in the global nuclear power plant (NPP) fleet, and these have an average age greater than 20 years. These NPPs had design lives of 30 or 40 years. The United States is currently implementing license extensions of 20 years on many plants and consideration is now being given to the concept of “life-beyond-60,” a further period of license extension from 60 to 80 years, and potentially longer. In almost all countries with NPPs, authorities are looking at some form of license renewal program. There is a growing urgency as a number of plants face either approvals for license extension or shut down, which will require deployment of new power plants. In support of NPP license extension over the past decade, various national and international programs have been initiated. This paper reports part of the work performed in support of the U.S. Nuclear Regulatory Commission’s (NRC’s) Proactive Management of Materials Degradation (PMMD) program. The paper concisely explains the basic principles of PMMD, its relationship to advanced diagnostics and prognostics and provides an assessment of some the technical gaps in PMMD and prognostics that need to be addressed.

  7. Land degradation, monitoring, and adapting land management for sustainability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land degradation impacts on agricultural production and other ecosystem services often far exceed those of climate change, yet these impacts are largely ignored. In September, the United Nations adopted a “land degradation neutrality” target as part of its Sustainable Development Agenda. This paper ...

  8. Damage Assessment technologies for Prognostics and Proactive Management of Materials Degradation (PMMD)

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Griffin, Jeffrey W.; Hull, Amy; Malik, Shah

    2009-04-17

    Summary for Special Session Invited paper "The Best of NPIC&HMIT 2009" The Nuclear Regulatory Commission has undertaken the Proactive Management of Materials Degradation (PMMD) program to lay the groundwork for defining proactive actions to manage degradation of materials in light water reactors (LWRs) including nuclear power plant structures, systems and components. The PMMD program is examining LWR component materials and the degradation phenomena that affect them. Of particular interest is how such phenomena can be monitored to predict degradation and prevent component failure.

  9. Modeling Suomi-NPP VIIRS Solar Diffuser Degradation due to Space Radiation

    NASA Astrophysics Data System (ADS)

    Shao, X.; Cao, C.

    2014-12-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi-NPP uses a solar diffuser (SD) as on-board radiometric calibrator for the reflective solar band (RSB) calibration. Solar diffuser is made of Spectralon (one type of fluoropolymer) and was chosen because of its controlled reflectance in the VIS-NIR-SWIR region and its near-Lambertian reflectance profile. Spectralon is known to degrade in reflectance at the blue end of the spectrum due to exposure to space radiations such as solar UV radiation and energetic protons. These space radiations can modify the Spectralon surface through breaking C-C and C-F bonds and scissioning or cross linking the polymer, which causes the surface roughness and degrades its reflectance. VIIRS uses a SDSM (Solar Diffuser Stability Monitor) to monitor the change in the Solar Diffuser reflectance in the 0.4 - 0.94 um wavelength range and provide a correction to the calibration constants. The H factor derived from SDSM reveals that reflectance of 0.4 to 0.6um channels of VIIRS degrades faster than the reflectance of longer wavelength RSB channels. A model is developed to derive characteristic parameters such as mean SD surface roughness height and autocovariance length of SD surface roughness from the long term spectral degradation of SD reflectance as monitored by SDSM. These two parameters are trended to assess development of surface roughness of the SD over the operation period of VIIRS.

  10. Damage Assessment Technologies for Prognostics and Proactive Management of Materials Degradation

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Griffin, Jeffrey W.; Hull, Amy B.; Malik, Shah

    2011-01-01

    The Nuclear Regulatory Commission has undertaken a program to lay the groundwork for defining proactive actions to manage degradation of materials in light water reactors (LWRs). This paper discusses the U.S. Nuclear Regulatory Commission’s Proactive Management of Materials Degradation (PMMD) program and its application to nuclear power plant structures, systems and components. The PMMD program is examining LWR component materials and the degradation phenomena that affect them. Of particular interest is how such phenomena can be monitored to predict degradation and prevent component failure. Some forms of degradation, including some modes of stress corrosion cracking, are characterized by a long initiation time followed by a rapid growth phase. Monitoring such long-term degradation will require new non-destructive evaluation (NDE) methods and measurement procedures. A critical analysis of all reactor components is required to determine if new inspection strategies are required to effectively manage slow degradation mechanisms that may lead to component failure. As reactor lifetimes are extended, degradation mechanisms previously considered too long-term to be of consequence (such as concrete and wiring insulation degradation) may become more important. This paper includes a review of techniques with potential for sensing and monitoring degradation in its early stages and will concisely explain the basic principles of PMMD and its relationship to in-service inspection, condition based maintenance, and advanced diagnostics and prognostics.

  11. Damage Assessment Technologies for Prognostics and Proactive Management of Materials Degradation

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Griffin, Jeffrey W.; Hull, Amy; Malik, Shah

    2011-02-26

    The Nuclear Regulatory Commission has undertaken a program to lay the groundwork for defining proactive actions to manage degradation of materials in light water reactors (LWRs). This paper discusses the U.S. Nuclear Regulatory Commission’s Proactive Management of Materials Degradation (PMMD) program and its application to nuclear power plant structures, systems and components. The PMMD program is examining LWR component materials and the degradation phenomena that affect them. Of particular interest is how such phenomena can be monitored to predict degradation and prevent component failure. Some forms of degradation, such as stress corrosion cracking, are characterized by a long initiation time followed by a rapid growth phase. Monitoring such long-term degradation will require new NDE methods and measurement procedures. A critical analysis of all reactor components is required to determine if new inspection strategies are required to effectively manage slow degradation mechanisms that may lead to component failure. As reactor lifetimes are extended, degradation mechanisms previously considered too long-term to be of consequence (such as concrete and wiring insulation degradation) may become more important. This paper includes a review of techniques with potential for sensing and monitoring degradation in its early stages and will concisely explain the basic principles of PMMD and its relationship to in-service inspection, condition based maintenance, and advanced diagnostics and prognostics.

  12. Degradation of thermal control materials under a simulated radiative space environment

    NASA Astrophysics Data System (ADS)

    Sharma, A. K.; Sridhara, N.

    2012-11-01

    A spacecraft with a passive thermal control system utilizes various thermal control materials to maintain temperatures within safe operating limits. Materials used for spacecraft applications are exposed to harsh space environments such as ultraviolet (UV) and particle (electron, proton) irradiation and atomic oxygen (AO), undergo physical damage and thermal degradation, which must be considered for spacecraft thermal design optimization and cost effectiveness. This paper describes the effect of synergistic radiation on some of the important thermal control materials to verify the assumptions of beginning-of-life (BOL) and end-of-life (EOL) properties. Studies on the degradation in the optical properties (solar absorptance and infrared emittance) of some important thermal control materials exposed to simulated radiative geostationary space environment are discussed. The current studies are purely related to the influence of radiation on the degradation of the materials; other environmental aspects (e.g., thermal cycling) are not discussed. The thermal control materials investigated herein include different kind of second-surface mirrors, white anodizing, white paints, black paints, multilayer insulation materials, varnish coated aluminized polyimide, germanium coated polyimide, polyether ether ketone (PEEK) and poly tetra fluoro ethylene (PTFE). For this purpose, a test in the constant vacuum was performed reproducing a three year radiative space environment exposure, including ultraviolet and charged particle effects on North/South panels of a geostationary three-axis stabilized spacecraft. Reflectance spectra were measured in situ in the solar range (250-2500 nm) and the corresponding solar absorptance values were calculated. The test methodology and the degradations of the materials are discussed. The most important degradations among the low solar absorptance materials were found in the white paints whereas the rigid optical solar reflectors remained quite

  13. Medical management of the acute radiation syndrome

    PubMed Central

    López, Mario; Martín, Margarita

    2011-01-01

    The acute radiation syndrome (ARS) occurs after whole-body or significant partial-body irradiation (typically at a dose of >1 Gy). ARS can involve the hematopoietic, cutaneous, gastrointestinal and the neurovascular organ systems either individually or in combination. There is a correlation between the severity of clinical signs and symptoms of ARS and radiation dose. Radiation induced multi-organ failure (MOF) describes the progressive dysfunction of two or more organ systems over time. Radiation combined injury (RCI) is defined as radiation injury combined with blunt or penetrating trauma, burns, blast, or infection. The classic syndromes are: hematopoietic (doses >2–3 Gy), gastrointestinal (doses 5–12 Gy) and cerebrovascular syndrome (doses 10–20 Gy). There is no possibility to survive after doses >10–12 Gy. The Phases of ARS are—prodromal: 0–2 days from exposure, latent: 2–20 days, and manifest illness: 21–60 days from exposure. Granulocyte-colony stimulating factor (G-CSF) at a dose of 5 μg/kg body weight per day subcutaneously has been recommended as treatment of neutropenia, and antibiotics, antiviral and antifungal agents for prevention or treatment of infections. If taken within the first hours of contamination, stable iodine in the form of nonradioactive potassium iodide (KI) saturates iodine binding sites within the thyroid and inhibits incorporation of radioiodines into the gland. Finally, if severe aplasia persists under cytokines for more than 14 days, the possibility of a hematopoietic stem cell (HSC) transplantation should be evaluated. This review will focus on the clinical aspects of the ARS, using the European triage system (METREPOL) to evaluate the severity of radiation injury, and scoring groups of patients for the general and specific management of the syndrome. PMID:24376971

  14. Poly(aryl ethers) and related polysiloxane copolymer molecular coatings: Preparation and radiation degradation

    NASA Technical Reports Server (NTRS)

    Mcgrath, J. E.

    1982-01-01

    The radiation degradation of poly(arylene ether sulfones) and related materials is studied. These basic studies are important both as a means to developing stronger, more stable matrix resins for composite materials, as well as to improve the data base in regard to chemical structure-physical property relationships. Thirty homo and copolymers were synthesized, at least partially characterized and, in several cases suitable film casting techniques were developed. Four samples were chosen for initial radiation degradation. Poly(dimethyl siloxane) soft bocks/segments can preferentially migrate to the surface of copolymer films. Since siloxanes are utilized as thermal control coatings, this form of 'molecular' coating is of interest. The chemistry for preparing such copolymers with any of the polymers described was demonstrated.

  15. Impacts of management practices on soil organic carbon in degraded alpine meadows on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chang, X. F.; Wang, S. P.; Zhu, X. X.; Cui, S. J.; Luo, C. Y.; Zhang, Z. H.; Wilkes, A.

    2014-01-01

    Grassland soil organic carbon (SOC) is sensitive to anthropogenic activities. Increased anthropogenic disturbance related to overgrazing has led to widespread alpine grassland degradation on the Tibetan Plateau. The degraded grasslands are considered to have great potential for carbon sequestration after adoption of improved management practices. Here, we calibrated and employed the Century model to investigate the effects of overgrazing and improved managements on the SOC dynamics in alpine meadows. We calibrated Century model against plant productivity at Haibei Research Station. SOC stocks for validation were obtained in 2009-2010 from degraded alpine meadows in two communes. We found that Century model can successfully capture grassland SOC changes. Overall, our simulation suggests that degraded alpine meadow SOC significantly increased with the advent of restoration managements from 2011 to 2030. Carbon sequestration rates ranged between 0.04 Mg C ha-1 yr-1 in lightly degraded winter grasslands and 2.0 Mg C ha-1 yr-1 in moderately degraded summer grasslands. Our modeling work also predicts that improve management in Tibetan degraded grasslands will contribute to an annual carbon sink of 0.022-0.059 Pg C yr-1. These results imply that restoration of degraded grasslands in Tibetan Plateau has great potential for soil carbon sequestration to mitigate greenhouse gases.

  16. Impacts of management practices on soil organic carbon in degraded alpine meadows on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chang, X. F.; Zhu, X. X.; Wang, S. P.; Cui, S. J.; Luo, C. Y.; Zhang, Z. H.; Wilkes, A.

    2014-07-01

    Grassland soil organic carbon (SOC) is sensitive to anthropogenic activities. Increased anthropogenic disturbance related to overgrazing has led to widespread alpine grassland degradation on the Tibetan Plateau. The degraded grasslands are considered to have great potential for carbon sequestration after adoption of improved management practices. Here, we calibrated and employed the Century model to investigate the effects of overgrazing and improved managements on the SOC dynamics in alpine meadows. We calibrated the Century model against plant productivity at the Haibei Research Station. SOC stocks for validation were obtained in 2009-2010 from degraded alpine meadows in two communes. We found that Century model can successfully capture grassland SOC changes. Overall, our simulation suggests that degraded alpine meadow SOC significantly increased with the advent of restoration management from 2011 to 2030. Carbon sequestration rates ranged between 0.04 Mg C ha-1 yr-1 in lightly degraded winter grazing grasslands and 2.0 Mg C ha-1 yr-1 in moderately degraded summer grazing grasslands. Our modelling work also predicts that improve management in degraded Tibetan grasslands will contribute to an annual carbon sink of 0.022-0.059 Pg C yr-1. These results imply that restoration of degraded grasslands in the Tibetan Plateau has great potential for soil carbon sequestration to mitigate greenhouse gases.

  17. Restoration of Degraded/Eroded Soil under Different Management Practices in the Central Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmlands in the Central Great Plains Region (CGPR) have lost topsoil through wind and water erosion induced by tillage and poor soil management. These soils are now degraded with low soil quality and productivity. Productivity and quality of degraded/eroded soils can be restored using manure and i...

  18. Effect of top electrode material on radiation-induced degradation of ferroelectric thin film structures

    NASA Astrophysics Data System (ADS)

    Brewer, Steven J.; Deng, Carmen Z.; Callaway, Connor P.; Paul, McKinley K.; Fisher, Kenzie J.; Guerrier, Jonathon E.; Rudy, Ryan Q.; Polcawich, Ronald G.; Jones, Jacob L.; Glaser, Evan R.; Cress, Cory D.; Bassiri-Gharb, Nazanin

    2016-07-01

    The effects of gamma irradiation on the dielectric and piezoelectric responses of Pb[Zr0.52Ti0.48]O3 (PZT) thin film stacks were investigated for structures with conductive oxide (IrO2) and metallic (Pt) top electrodes. The samples showed, generally, degradation of various key dielectric, ferroelectric, and electromechanical responses when exposed to 2.5 Mrad (Si) 60Co gamma radiation. However, the low-field, relative dielectric permittivity, ɛr, remained largely unaffected by irradiation in samples with both types of electrodes. Samples with Pt top electrodes showed substantial degradation of the remanent polarization and overall piezoelectric response, as well as pinching of the polarization hysteresis curves and creation of multiple peaks in the permittivity-electric field curves post irradiation. The samples with oxide electrodes, however, were largely impervious to the same radiation dose, with less than 5% change in any of the functional characteristics. The results suggest a radiation-induced change in the defect population or defect energy in PZT with metallic top electrodes, which substantially affects motion of internal interfaces such as domain walls. Additionally, the differences observed for stacks with different electrode materials implicate the ferroelectric-electrode interface as either the predominant source of radiation-induced effects (Pt electrodes) or the site of healing for radiation-induced defects (IrO2 electrodes).

  19. Endoscopic management of chronic radiation proctitis

    PubMed Central

    Rustagi, Tarun; Mashimo, Hiroshi

    2011-01-01

    Chronic radiation proctopathy occurs in 5%-20% of patients following pelvic radiotherapy. Although many cases resolve spontaneously, some lead to chronic symptoms including diarrhea, tenesmus, urgency and persistent rectal bleeding with iron deficiency anemia requiring blood transfusions. Treatments for chronic radiation proctitis remain unsatisfactory and the basis of evidence for various therapies is generally insufficient. There are very few controlled or prospective trials, and comparisons between therapies are limited because of different evaluation methods. Medical treatments, including formalin, topical sucralfate, 5-amino salicylic acid enemas, and short chain fatty acids have been used with limited success. Surgical management is associated with high morbidity and mortality. Endoscopic therapy using modalities such as the heater probe, neodymium:yttrium-aluminium-garnet laser, potassium titanyl phosphate laser and bipolar electrocoagulation has been reported to be of some benefit, but with frequent complications. Argon plasma coagulation is touted to be the preferred endoscopic therapy due to its efficacy and safety profile. Newer methods of endoscopic ablation such as radiofrequency ablation and cryotherapy have been recently described which may afford broader areas of treatment per application, with lower rate of complications. This review will focus on endoscopic ablation therapies, including such newer modalities, for chronic radiation proctitis. PMID:22147960

  20. The History and Future of NDE in the Management of Nuclear Power Plant Materials Degradation

    SciTech Connect

    Doctor, Steven R.

    2009-04-01

    The author has spent more than 25 years conducting engineering and research studies to quantify the performance of nondestructive evaluation (NDE) in nuclear power plant (NPP) applications and identifying improvements to codes and standards for NDE to manage materials degradation. This paper will review this fundamental NDE engineering/research work and then look to the future on how NDE can be optimized for proactively managing materials degradation in NPP components.

  1. Evaluation and Selection of Indicators for Land Degradation and Desertification Monitoring: Types of Degradation, Causes, and Implications for Management

    NASA Astrophysics Data System (ADS)

    Kairis, Or.; Kosmas, C.; Karavitis, Ch.; Ritsema, C.; Salvati, L.; Acikalin, S.; Alcalá, M.; Alfama, P.; Atlhopheng, J.; Barrera, J.; Belgacem, A.; Solé-Benet, A.; Brito, J.; Chaker, M.; Chanda, R.; Coelho, C.; Darkoh, M.; Diamantis, I.; Ermolaeva, O.; Fassouli, V.; Fei, W.; Feng, J.; Fernandez, F.; Ferreira, A.; Gokceoglu, C.; Gonzalez, D.; Gungor, H.; Hessel, R.; Juying, J.; Khatteli, H.; Khitrov, N.; Kounalaki, A.; Laouina, A.; Lollino, P.; Lopes, M.; Magole, L.; Medina, L.; Mendoza, M.; Morais, P.; Mulale, K.; Ocakoglu, F.; Ouessar, M.; Ovalle, C.; Perez, C.; Perkins, J.; Pliakas, F.; Polemio, M.; Pozo, A.; Prat, C.; Qinke, Y.; Ramos, A.; Ramos, J.; Riquelme, J.; Romanenkov, V.; Rui, L.; Santaloia, F.; Sebego, R.; Sghaier, M.; Silva, N.; Sizemskaya, M.; Soares, J.; Sonmez, H.; Taamallah, H.; Tezcan, L.; Torri, D.; Ungaro, F.; Valente, S.; de Vente, J.; Zagal, E.; Zeiliguer, A.; Zhonging, W.; Ziogas, A.

    2014-11-01

    Indicator-based approaches are often used to monitor land degradation and desertification from the global to the very local scale. However, there is still little agreement on which indicators may best reflect both status and trends of these phenomena. In this study, various processes of land degradation and desertification have been analyzed in 17 study sites around the world using a wide set of biophysical and socioeconomic indicators. The database described earlier in this issue by Kosmas and others (Environ Manage, 2013) for defining desertification risk was further analyzed to define the most important indicators related to the following degradation processes: water erosion in various land uses, tillage erosion, soil salinization, water stress, forest fires, and overgrazing. A correlation analysis was applied to the selected indicators in order to identify the most important variables contributing to each land degradation process. The analysis indicates that the most important indicators are: (i) rain seasonality affecting water erosion, water stress, and forest fires, (ii) slope gradient affecting water erosion, tillage erosion and water stress, and (iii) water scarcity soil salinization, water stress, and forest fires. Implementation of existing regulations or policies concerned with resources development and environmental sustainability was identified as the most important indicator of land protection.

  2. Evaluation and selection of indicators for land degradation and desertification monitoring: types of degradation, causes, and implications for management.

    PubMed

    Kairis, Or; Kosmas, C; Karavitis, Ch; Ritsema, C; Salvati, L; Acikalin, S; Alcalá, M; Alfama, P; Atlhopheng, J; Barrera, J; Belgacem, A; Solé-Benet, A; Brito, J; Chaker, M; Chanda, R; Coelho, C; Darkoh, M; Diamantis, I; Ermolaeva, O; Fassouli, V; Fei, W; Feng, J; Fernandez, F; Ferreira, A; Gokceoglu, C; Gonzalez, D; Gungor, H; Hessel, R; Juying, J; Khatteli, H; Khitrov, N; Kounalaki, A; Laouina, A; Lollino, P; Lopes, M; Magole, L; Medina, L; Mendoza, M; Morais, P; Mulale, K; Ocakoglu, F; Ouessar, M; Ovalle, C; Perez, C; Perkins, J; Pliakas, F; Polemio, M; Pozo, A; Prat, C; Qinke, Y; Ramos, A; Ramos, J; Riquelme, J; Romanenkov, V; Rui, L; Santaloia, F; Sebego, R; Sghaier, M; Silva, N; Sizemskaya, M; Soares, J; Sonmez, H; Taamallah, H; Tezcan, L; Torri, D; Ungaro, F; Valente, S; de Vente, J; Zagal, E; Zeiliguer, A; Zhonging, W; Ziogas, A

    2014-11-01

    Indicator-based approaches are often used to monitor land degradation and desertification from the global to the very local scale. However, there is still little agreement on which indicators may best reflect both status and trends of these phenomena. In this study, various processes of land degradation and desertification have been analyzed in 17 study sites around the world using a wide set of biophysical and socioeconomic indicators. The database described earlier in this issue by Kosmas and others (Environ Manage, 2013) for defining desertification risk was further analyzed to define the most important indicators related to the following degradation processes: water erosion in various land uses, tillage erosion, soil salinization, water stress, forest fires, and overgrazing. A correlation analysis was applied to the selected indicators in order to identify the most important variables contributing to each land degradation process. The analysis indicates that the most important indicators are: (i) rain seasonality affecting water erosion, water stress, and forest fires, (ii) slope gradient affecting water erosion, tillage erosion and water stress, and (iii) water scarcity soil salinization, water stress, and forest fires. Implementation of existing regulations or policies concerned with resources development and environmental sustainability was identified as the most important indicator of land protection. PMID:23811772

  3. Radiation-induced 1/f noise degradation of PNP bipolar junction transistors at different dose rates

    NASA Astrophysics Data System (ADS)

    Qi-Feng, Zhao; Yi-Qi, Zhuang; Jun-Lin, Bao; Wei, Hu

    2016-04-01

    It is found that ionizing-radiation can lead to the base current and the 1/f noise degradations in PNP bipolar junction transistors. In this paper, it is suggested that the surface of the space charge region of the emitter-base junction is the main source of the base surface 1/f noise. A model is developed which identifies the parameters and describes their interactive contributions to the recombination current at the surface of the space charge region. Based on the theory of carrier number fluctuation and the model of surface recombination current, a 1/f noise model is developed. This model suggests that 1/f noise degradations are the result of the accumulation of oxide-trapped charges and interface states. Combining models of ELDRS, this model can explain the reason why the 1/f noise degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 700 Gy(Si). The low dose rate was 0.001 Gy(Si)/s and the high dose rate was 0.1 Gy(Si)/s. The model accords well with the experimental results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61076101 and 61204092).

  4. Degradation of Silicone Oils Exposed to Geostationary Environment Components: Ultraviolet Radiations and Electron Flux

    NASA Astrophysics Data System (ADS)

    Jochem, H.; Rejsek-Riba, V.; Maerten, E.; Baceiredo, A.; Remaury, S.

    Degradation of polydimethylsiloxane and vinyl-terminated polydimethylsiloxane oils exposed to UV radiation or 1.25 MeV electron flux was investigated using EPR, GC Headspace, NMR, GPC and UV-vis-NIR spectroscopy. To examine the influence of synthetic method, these two oils were prepared by ring opening polymerization using either an inorganic initiator KOH or an organic catalyst N-Heterocyclic carbene. Under UV radiation, any chemical change is observed for polydimethylsiloxane, whereas vinyl-terminated polydimethylsiloxane presents a decrease of vinyl functions and an increase of chain length. Both polydimethylsiloxane and vinyl terminated polydimethylsiloxane demonstrated a degradation of thermo-optical properties, more significant for oils synthesized with organic catalyst. By improving oil purification, the degradation of thermo-optical properties can be reduced. Effects of electron flux are similar for each oil, thus independently of synthetic method and end functions. Electron flux generates important chemical damages initiated by homolytic chain scissions. Radical recombination produces gases (methane and ethane), new functions (Si-H) and bonds across silicone chains leading to a solid state material. Crosslinking of chains occurs by formation of R-Si-(O)3 and Si-CH2-Si groups. Silyl radicals are trapped in the polymer network and can be detected even 1 week after the end of irradiation.

  5. Reductive degradation of tetrabromobisphenol A over iron-silver bimetallic nanoparticles under ultrasound radiation.

    PubMed

    Luo, Si; Yang, Shaogui; Wang, Xiaodong; Sun, Cheng

    2010-04-01

    The present study described the degradation behavior of tetrabromobisphenol A (TBBPA) in Fe-Ag suspension solutions under ultrasonic radiation (US). The Fe-Ag bimetallic nanoparticles with core-shell structure were successfully synthesized by reduction and deposition of Ag on nanoscale Fe surface, and were further characterized by BET, XRD, TEM, SEM, X-ray fluorescence and X-ray photo-electron spectroscopy. The results revealed that the displacement plating produced a non-uniform overlayer of Ag additive on iron; the as-synthesized bimetallic nanoparticles were spherical with diameters of 20-100 nm aggregated in the form of chains. Batch studies demonstrated that the TBBPA (2 mg L(-1)) was completely degraded in 20 min over Fe-Ag nanoparticles, which has higher degradation efficiency than Fe(0) nanoparticles under US. The effects of Fe-Ag bimetallic nanoparticles loading, initial TBBPA concentration, pH of the solution, Ag loading and temperature on the reduction efficiency of TBBPA under US were investigated. The complete reduction of TBBPA in 20 min was determined selectively under the conditions of pH (pH=6.0+/-0.5), Ag loading(1 wt.%) at 30 degrees C over the fabricated Fe-Ag nanoparticles. Additionally, the major intermediates identified by LC-MS technique were tri-BBPA, di-BBPA, mono-BBPA and BPA and the degradation mechanism was also proposed. PMID:20236681

  6. Radiation induced oxidative degradation of polymers—III. Effect of radiation on mechanical properties

    NASA Astrophysics Data System (ADS)

    Seguchi, Tadao; Arakawa, Kazuo; Ito, Masayuki; Hayakawa, Naohiro; Machi, Sueo

    The changes of mechanical properties of various kinds of polyethylene (PE) and ethylene-propylene copolymer (EPR) with the irradiation in air, in oxygen of 10 atm, and under vacuum were investigated. The decrease in the elongation ( E b) and the tensile strength ( T b) of PE by the irradiation in oxygen is larger than under vacuum. The changes of E b well reflect the degradation of PE. In case of EPR, the T b decreases sharply with dose in any environments, and the E b decreases under vacuum to a larger extent than in oxygen. The modulus at 200% elongation of EPR increases with dose under vacuum, but decreases in oxygen. When the samples were irradiated in air, the changes of the mechanical properties were the intermediate between oxygen and vacuum and dependent on the ratio of oxidation and non-oxidation layers in the film. The antioxidant (Irganox 1010 or DPPD) mixed in polymers was found to retard effectively the polymer degradation by the irradiation in oxygen.

  7. Best Management Practices for Remediation/Restoration of Degraded Soils in the Central Great Plains Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmlands in the Central Great Plains Region (CGPR) have lost topsoil through wind and water erosion induced by tillage and poor soil management (Wheat-fallow management). Productivity of degraded/eroded soils can be restored using organic amendment such as manure and improved crop and soil manageme...

  8. Radiation-induced electrical degradation experiments in the Japan materials testing reactor

    SciTech Connect

    Farnum, E.; Scharborough, K.; Shikama, Tatsuo

    1995-04-01

    The objective of this experiment is to determine the extent of degradation during neutron irradiation of electrical and optical properties of candidate dielectric materials. The goals are to identify promising dielectrics for ITER and other fusion machines for diagnostic applications and establish the basis for optimization of candidate materials. An experiment to measure radiation-induced electrical degradation (REID) in sapphire and MgO-insulated cables was conducted at the JMTR light water reactor. The materials were irradiated at about 260 {degree}C to a fluence of 3{times}10{sup 24} n/m{sup 2} (E>1 MeV) with an applied DC electric field between 100 kV/m and 500 kV/m.

  9. Radiation-induced degradation of hydroxyapatite/poly L-lactide composite biomaterial

    NASA Astrophysics Data System (ADS)

    Suljovrujić, E.; Ignjatović, N.; Uskoković, D.; Mitrić, M.; Mitrović, M.; Tomić, S.

    2007-04-01

    The effects of gamma irradiation on the structure and properties of hydroxyapatite/poly L-lactide (HAp/PLLA) biomaterial have been investigated. Effects of radiation on microstructure, degradation of polymer part and thermal stability of composite were determined by scanning electronic microscopy (SEM), gel permeation chromatography (GPC) and thermogravimetric analysis (TGA), respectively. Mechanical properties were obtained through mechanical strength and elasticity modulus. Presented results show that properties of HAp/PLLA decay with irradiation dose, but for doses required for sterilization, changes and damaging effects are acceptable.

  10. Performance of an electrically raised, synchronous satellite when subjected to radiation degradation effects

    NASA Technical Reports Server (NTRS)

    Cake, J. E.; Regetz, J. D., Jr.

    1971-01-01

    The use of solar electric propulsion to raise a high-power communication satellite from a low altitude, inclined circular orbit of the geosynchronous orbit is evaluated. Since the satellite ascends through the high intensity radiation belts, the power available from the solar array and therefore to the ion thrusters degrades. The performance of the solar electric stage in combination with the thrust augmented Thor/Delta launch vehicle is evaluated for two thrust steering programs. The transfer times and solar array requirements are presented for total geosynchronous payloads from 450 to 1100 kg.

  11. Degradation of Teflon(trademark) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Townsend, Jacqueline; Powers, Charles; Viens, Michael; Ayres-Treusdell, Mary; Munoz, Bruno

    1999-01-01

    During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon(trademark) FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon(trademark) FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon(trademark) FEP.

  12. Degradation of Teflon(tm) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Townsend, Jacqueline A.; Powers, Charles E.; Viens, Michael J.; Ayres-Treusdell, Mary T.; Munoz, Bruno

    1998-01-01

    During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon' FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon FEP.

  13. Degradation of Teflon(tm) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Townsend, Jacqueline A.; Powers, Charles E.; Viens, Michael J.; Ayres-Treusdell, Mary T.; Munoz, Bruno F.

    1998-01-01

    During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon' FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon(registered trademark) FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon(registered trademark) FEP.

  14. Degradation of Teflon(tm) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Townsend, Jacqueline; Powers, Charles; Viens, Michael; Ayres-Treusdell, Mary; Munoz, Bruno

    1998-01-01

    During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon(R) FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon(R) FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon(R) FEP.

  15. Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradation

    SciTech Connect

    Remec, Igor; Rosseel, Thomas M; Field, Kevin G; Pape, Yann Le

    2016-01-01

    Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete with a particular focus on radiation-induced effects. Based on the projected neutron fluence (E > 0.1 MeV) values in the concrete biological shields of the US PWR fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to assure reliable risk assessment for NPPs extended operation.

  16. Prediction of ionizing radiation effects induced performance degradation in homodyne BPSK based inter-satellite optical communication systems

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Li, Xuan; Dong, Chen

    2016-03-01

    Ionizing radiation effects induced on-orbit performance degradation in homodyne binary phase shift keying (BPSK) based inter-satellite optical communication system is predicted in this paper. Essential optoelectronic devices involved in optical communication system were irradiated by Co60 gamma ray and ionizing radiation environment of three general orbits was analyzed. On this basis, variations of terminal performance loss and system BER degradation along with on-orbit working time were simulated. Influences of terminal location and orbit environment were further discussed. Radiation protection on laser transmitters requires more strengthening, especially for those located in MEO and GEO satellites.

  17. Reorienting land degradation towards sustainable land management: linking sustainable livelihoods with ecosystem services in rangeland systems.

    PubMed

    Reed, M S; Stringer, L C; Dougill, A J; Perkins, J S; Atlhopheng, J R; Mulale, K; Favretto, N

    2015-03-15

    This paper identifies new ways of moving from land degradation towards sustainable land management through the development of economic mechanisms. It identifies new mechanisms to tackle land degradation based on retaining critical levels of natural capital whilst basing livelihoods on a wider range of ecosystem services. This is achieved through a case study analysis of the Kalahari rangelands in southwest Botswana. The paper first describes the socio-economic and ecological characteristics of the Kalahari rangelands and the types of land degradation taking place. It then focuses on bush encroachment as a way of exploring new economic instruments (e.g. Payments for Ecosystem Services) designed to enhance the flow of ecosystem services that support livelihoods in rangeland systems. It does this by evaluating the likely impacts of bush encroachment, one of the key forms of rangeland degradation, on a range of ecosystem services in three land tenure types (private fenced ranches, communal grazing areas and Wildlife Management Areas), before considering options for more sustainable land management in these systems. We argue that with adequate policy support, economic mechanisms could help reorient degraded rangelands towards more sustainable land management. PMID:25617787

  18. Radiation induced degradation of polychlorinated biphenyls (PCBs) pollutants in paint scrapings.

    PubMed

    Singh, R K; Khandal, R K; Singh, Gurdeep

    2009-01-01

    Polychlorinated biphenyls (PCBs) are synthetic organic chemicals which have been commercially used worldwide in many specialty applications. In paints, PCBs were used because of their unique properties such as thermal stability, flame-resistance and low volatility. However, due to their adverse effects on human health and environment, the use of PCBs has now been banned. PCBs are today considered widespread pollutants in the global system . PCBs sources still exist in various products and in waste streams such as oil, paints, rubbers etc. Various remedial technologies have been developed in the world to detoxify PCBs. In the present study, radiolysis has been investigated as a safe means to reduce or destroy PCBs. Under this study, detoxification of PCBs in paint scrapings by gamma radiation using Cobalt 60 source has been investigated. The experimental results demonstrate that the gamma radiations can be an alternative environment- friendly technology for destroying PCBs. Gamma radiations also have the potential of being a preferred tool in comparison to the most widely used incineration method for destroying PCBs. The method used was found highly effective and destruction efficiency was as high as 91%. The degradation efficiency of PCBs was dependent on absorbed radiation dose, the type of PCBs and also on the source of paint scrapings. PMID:21114157

  19. Nano-JASMINE: cosmic radiation degradation of CCD performance and centroid detection

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yukiyasu; Shimura, Yuki; Niwa, Yoshito; Yano, Taihei; Gouda, Naoteru; Yamada, Yoshiyuki

    2012-09-01

    Nano-JASMINE (NJ) is a very small astrometry satellite project led by the National Astronomical Observatory of Japan. The satellite is ready for launch, and the launch is currently scheduled for late 2013 or early 2014. The satellite is equipped with a fully depleted CCD and is expected to perform astrometry observations for stars brighter than 9 mag in the zw-band (0.6 µm-1.0 µm). Distances of stars located within 100 pc of the Sun can be determined by using annual parallax measurements. The targeted accuracy for the position determination of stars brighter than 7.5 mag is 3 mas, which is equivalent to measuring the positions of stars with an accuracy of less than one five-hundredth of the CCD pixel size. The position measurements of stars are performed by centroiding the stellar images taken by the CCD that operates in the time and delay integration mode. The degradation of charge transfer performance due to cosmic radiation damage in orbit is proved experimentally. A method is then required to compensate for the effects of performance degradation. One of the most effective ways of achieving this is to simulate observed stellar outputs, including the effect of CCD degradation, and then formulate our centroiding algorithm and evaluate the accuracies of the measurements. We report here the planned procedure to simulate the outputs of the NJ observations. We also developed a CCD performance-measuring system and present preliminary results obtained using the system.

  20. Stability and Degradation Mechanisms of Radiation-Grafted Polymer Electrolyte Membranes for Water Electrolysis.

    PubMed

    Albert, Albert; Lochner, Tim; Schmidt, Thomas J; Gubler, L

    2016-06-22

    Radiation-grafted membranes are a promising alternative to commercial membranes for water electrolyzers, since they exhibit lower hydrogen crossover and area resistance, better mechanical properties, and are of potentially lower cost than perfluoroalkylsulfonic acid membranes, such as Nafion. Stability is an important factor in view of the expected lifetime of 40 000 h or more of an electrolyzer. In this study, combinations of styrene (St), α-methylstyrene (AMS), acrylonitrile (AN), and 1,3-diisopropenylbenzene (DiPB) are cografted into 50 μm preirradiated poly(ethylene-co-tetrafluoroethylene) (ETFE) base film, followed by sulfonation to produce radiation-grafted membranes. The stability of the membranes with different monomer combinations is compared under an accelerated stress test (AST), and the degradation mechanisms are investigated. To mimic the conditions in an electrolyzer, in which the membrane is always in contact with liquid water at elevated temperature, the membranes are immersed in water for 5 days at 90 °C, so-called thermal stress test (TST). In addition to testing in air atmosphere tests are also carried out under argon to investigate the effect of the absence of oxygen. The water is analyzed with UV-vis spectroscopy and ion chromatography. The ion exchange capacity (IEC), swelling degree, and Fourier transform infrared (FTIR) spectra of the membranes are compared before and after the test. Furthermore, energy-dispersive X-ray (EDX) spectroscopic analysis of the membrane cross-section is performed. Finally, the influence of the TST to the membrane area resistance and hydrogen crossover is measured. The stability increases along the sequence St/AN, St/AN/DiPB, AMS/AN, and AMS/AN/DiPB grafted membrane. The degradation at the weak-link, oxygen-induced degradation, and hydrothermal degradation are proposed in addition to the "swelling-induced detachment" reported in the literature. By mitigating the possible paths of degradation, the AMS

  1. An economic evaluation of solar radiation management.

    PubMed

    Aaheim, Asbjørn; Romstad, Bård; Wei, Taoyuan; Kristjánsson, Jón Egill; Muri, Helene; Niemeier, Ulrike; Schmidt, Hauke

    2015-11-01

    Economic evaluations of solar radiation management (SRM) usually assume that the temperature will be stabilized, with no economic impacts of climate change, but with possible side-effects. We know from experiments with climate models, however, that unlike emission control the spatial and temporal distributions of temperature, precipitation and wind conditions will change. Hence, SRM may have economic consequences under a stabilization of global mean temperature even if side-effects other than those related to the climatic responses are disregarded. This paper addresses the economic impacts of implementing two SRM technologies; stratospheric sulfur injection and marine cloud brightening. By the use of a computable general equilibrium model, we estimate the economic impacts of climatic responses based on the results from two earth system models, MPI-ESM and NorESM. We find that under a moderately increasing greenhouse-gas concentration path, RCP4.5, the economic benefits of implementing climate engineering are small, and may become negative. Global GDP increases in three of the four experiments and all experiments include regions where the benefits from climate engineering are negative. PMID:26057725

  2. Degradation of microbial fluorescence biosignatures by solar ultraviolet radiation on Mars

    NASA Astrophysics Data System (ADS)

    Dartnell, Lewis R.; Patel, Manish R.

    2014-04-01

    Recent and proposed robotic missions to Mars are equipped with implements to expose or excavate fresh material from beneath the immediate surface. Once brought into the open, any organic molecules or potential biosignatures of present or past life will be exposed to the unfiltered solar ultraviolet (UV) radiation and face photolytic degradation over short time courses. The key question, then, is what is the window of opportunity for detection of recently exposed samples during robotic operations? Detection of autofluorescence has been proposed as a simple method for surveying or triaging samples for organic molecules. Using a Mars simulation chamber we conduct UV exposures on thin frozen layers of two model microorganisms, the radiation-resistant polyextremophile Deinococcus radiodurans and the cyanobacterium Synechocystis sp. PCC 6803. Excitation-emission matrices (EEMs) are generated of the full fluorescence response to quantify the change in signal of different cellular fluorophores over Martian equivalent time. Fluorescence of Deinococcus cells, protected by a high concentration of carotenoid pigments, was found to be relatively stable over 32 h of Martian UV irradiation, with around 90% of the initial signal remaining. By comparison, fluorescence from protein-bound tryptophan in Synechocystis is much more sensitive to UV photodegradation, declining to 50% after 64 h exposure. The signal most readily degraded by UV irradiation is fluorescence of the photosynthetic pigments - diminished to only 35% after 64 h. This sensitivity may be expected as the biological function of chlorophyll and phycocyanin is to optimize the harvesting of light energy and so they are readily photobleached. A significant increase in a ~450 nm emission feature is interpreted as accumulation of fluorescent cellular degradation products from photolysis. Accounting for diurnal variation in Martian sunlight, this study calculates that frozen cellular biosignatures would remain detectable by

  3. Developing Effective Continuous On-Line Monitoring Technologies to Manage Service Degradation of Nuclear Power Plants

    SciTech Connect

    Meyer, Ryan M.; Ramuhalli, Pradeep; Bond, Leonard J.; Cumblidge, Stephen E.

    2011-09-30

    Recently, there has been increased interest in using prognostics (i.e, remaining useful life (RUL) prediction) for managing and mitigating aging effects in service-degraded passive nuclear power reactor components. A vital part of this philosophy is the development of tools for detecting and monitoring service-induced degradation. Experience with in-service degradation has shown that rapidly-growing cracks, including several varieties of stress corrosion cracks (SCCs), can grow through a pipe in less than one fuel outage cycle after they initiate. Periodic inspection has limited effectiveness at detecting and managing such degradation requiring a more versatile monitoring philosophy. Acoustic emission testing (AET) and guided wave ultrasonic testing (GUT) are related technologies with potential for on-line monitoring applications. However, harsh operating conditions within NPPs inhibit the widespread implementation of both technologies. For AET, another hurdle is the attenuation of passive degradation signals as they travel though large components, relegating AET to targeted applications. GUT is further hindered by the complexity of GUT signatures limiting its application to the inspection of simple components. The development of sensors that are robust and inexpensive is key to expanding the use of AET and GUT for degradation monitoring in NPPs and improving overall effectiveness. Meanwhile, the effectiveness of AET and GUT in NPPs can be enhanced through thoughtful application of tandem AET-GUT techniques.

  4. Managing the adverse effects of radiation therapy.

    PubMed

    Berkey, Franklin J

    2010-08-15

    Nearly two thirds of patients with cancer will undergo radiation therapy as part of their treatment plan. Given the increased use of radiation therapy and the growing number of cancer survivors, family physicians will increasingly care for patients experiencing adverse effects of radiation. Selective serotonin reuptake inhibitors have been shown to significantly improve symptoms of depression in patients undergoing chemotherapy, although they have little effect on cancer-related fatigue. Radiation dermatitis is treated with topical steroids and emollient creams. Skin washing with a mild, unscented soap is acceptable. Cardiovascular disease is a well-established adverse effect in patients receiving radiation therapy, although there are no consensus recommendations for cardiovascular screening in this population. Radiation pneumonitis is treated with oral prednisone and pentoxifylline. Radiation esophagitis is treated with dietary modification, proton pump inhibitors, promotility agents, and viscous lidocaine. Radiation-induced emesis is ameliorated with 5-hydroxytryptamine3 receptor antagonists and steroids. Symptomatic treatments for chronic radiation cystitis include anticholinergic agents and phenazopyridine. Sexual dysfunction from radiation therapy includes erectile dysfunction and vaginal stenosis, which are treated with phosphodiesterase type 5 inhibitors and vaginal dilators, respectively. PMID:20704169

  5. LWR Aging Management Using a Proactive Approach to Control Materials Degradation

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Cumblidge, Stephen E.; Bruemmer, Stephen M.; Taylor, W Boyd; Hull, Amy; Malik, Shah

    2009-05-12

    Material issues can be the limiting factor for the operation of nuclear power plants. There is growing interest in new and improved philosophies and methodolgies for plant life management, which include the migration from reliance on periodic inservice inspection to include condition-based maintenance. A further step in the development of plant management is the move from proactive responses based on ISI to become proactive, through the investigation of the potential for implementation of a proactive management of materials degradation program and its potential impact on the managements of LWRs

  6. Failure Prevention For Nuclear Power Plants Through Proactive Management of Materials Degradation (PMMD)

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Bruemmer, Stephen M.; Cumblidge, Stephen E.; Hull, Amy; Malik, Shah

    2009-05-01

    Failure prevention is central to the operation of nuclear power plants. To meet this goal there is growing interest in new and improved philosophies and methodologies for plant life management (PLiM), which include the migration from reliance on periodic inservice inspection to include condition-based maintenance. A further step in the development of plant management is the move from reactive responses based on ISI to become proactive, through the investigation of the potential for implementation of a proactive management of materials degradation (PMMD) program and its potential impact on the management of LWRs.

  7. Management of Dysphonia After Radiation Therapy.

    PubMed

    Villari, Craig R; Courey, Mark S

    2015-08-01

    Radiation-induced dysphonia can develop after radiation for primary laryngeal cancer or when the larynx is in the radiation field for nonlaryngeal malignancy. The effects are dose dependent and lead to variable degrees of dysphonia in both short- and long-term follow-up. Rehabilitation of the irradiated larynx can prove frustrating but can be facilitated through behavioral, pharmacologic, or surgical interventions. PMID:26092762

  8. Analysis of Radiation Induced Degradation in FPC-461 Fluoropolymers by Variable Temperature Multinuclear NMR

    SciTech Connect

    Chinn, S C; Wilson, T S; Maxwell, R S

    2004-10-27

    Solid state nuclear magnetic resonance techniques have been used to investigate aging mechanisms in a vinyl chloride:chlorotrifluoroethylene copolymer, FPC-461, due to exposure to {gamma}-radiation. Solid state {sup 1}H MAS NMR spectra revealed structural changes of the polymer upon irradiation under both air and nitrogen atmospheres. Considerable degradation is seen with {sup 1}H NMR in the vinyl chloride region of the polymer, particularly in the samples irradiated in air. {sup 19}F MAS NMR was used to investigate speciation in the chlorotrifluoroethylene blocks, though negligible changes were seen. {sup 1}H and {sup 19}F NMR at elevated temperature revealed increased segmental mobility and decreased structural heterogeneity within the polymer, yielding significant resolution enhancement over room temperature solid state detection. The effects of multi-site exchange are manifest in both the {sup 1}H and {sup 19}F NMR spectra as a line broadening and change in peak position as a function of temperature.

  9. Directional Degradation of Spectralon Diffuser Under Ionizing Radiation for Calibration of Space-Based Sensors

    NASA Technical Reports Server (NTRS)

    Georgiev, G. T.; Butler, J. J.; Kowalewski, M. G.; Ding, L.

    2012-01-01

    Assessment of the effect of Vacuum Ultra Violet (VUV) irradiation on the Bidirectional Reflectance Distribution Function (BRDF) of Spectralon is presented in this paper. The sample was a 99% white Spectralon calibration standard irradiated with VUV source positioned at 60o off the irradiation direction for a total of 20 hours. The BRDF before and after VUV irradiation was measured and compared at number of wavelengths in the UV, VIS and IR. Non-isotropic directional degradation of Spectralon diffuser under ionizing radiation was detected at different BRDF measurement geometries primarily at UV spectral range. The 8o directional/hemispherical reflectance of the same sample was also measured and compared from 200nm to 2500nm. Index Terms BRDF, Reflectance, Multiangular, Spectralon, Remote Sensing

  10. Dynamics of chromosomal aberrations, induction of apoptosis, BRCA2 degradation and sensitization to radiation by hyperthermia.

    PubMed

    Bergs, Judith W J; Oei, Arlene L; Ten Cate, Rosemarie; Rodermond, Hans M; Stalpers, Lukas J; Barendsen, Gerrit W; Franken, Nicolaas A P

    2016-07-01

    Hyperthermia can transiently degrade BRCA2 and thereby inhibit the homologous recombination pathway. Induced DNA-double strand breaks (DSB) then have to be repaired via the error prone non-homologous end-joining pathway. In the present study, to investigate the role of hyperthermia in genotoxicity and radiosensitization, the induction of chromosomal aberrations was examined by premature chromosome condensation and fluorescence in situ hybridisation (PCC-FISH), and cell survival was determined by clonogenic assay shortly (0-1 h) and 24 h following exposure to hyperthermia in combination with ionizing radiation. Prior to exposure to 4 Gy γ-irradiation, confluent cultures of SW‑1573 (human lung carcinoma) and RKO (human colorectal carcinoma) cells were exposed to mild hyperthermia (1 h, 41˚C). At 1 h, the frequency of chromosomal translocations was higher following combined exposure than following exposure to irradiation alone. At 24 h, the number of translocations following combined exposure was lower than following exposure to irradiation only, and was also lower than at 1 h following combined exposure. These dynamics in translocation frequency can be explained by the hyperthermia-induced transient reduction of BRCA2 observed in both cell lines. In both cell lines exposed to radiation only, potentially lethal damage repair (PLDR) correlated with a decreased number of chromosomal fragments at 24 h compared to 1 h. With combined exposure, PLDR did not correlate with a decrease in fragments, as in the RKO cells at 24 h following combined exposure, the frequency of fragments remained at the level found after 1 h of exposure and was also significantly higher than that found following exposure to radiation alone. This was not observed in the SW‑1573 cells. Cell survival experiments demonstrated that exposure to hyperthermia radiosensitized the RKO cells, but not the SW‑1573 cells. This radiosensitization was at least partly due to the induction

  11. Forward-biased current annealing of radiation degraded indium phosphide and gallium arsenide solar cells

    NASA Technical Reports Server (NTRS)

    Michael, Sherif; Cypranowski, Corinne; Anspaugh, Bruce

    1990-01-01

    The preliminary results of a novel approach to low-temperature annealing of previously irradiated indium phosphide and gallium arsenide solar cells are reported. The technique is based on forward-biased current annealing. The two types of III-V solar cells were irradiated with 1-MeV electrons to a fluence level of (1-10) x 10 to the 14th electrons/sq cm. Several annealing attempts were made, varying all conditions. Optimum annealing was achieved when cells were injected with minority currents at a constant 90 C. The current density for each type of cell was also determined. Significant recovery of degraded parameters was achieved in both cases. However, the InP cell recovery notably exceeded the recovery in GaAs cells. The recovery is thought to be caused by current-stimulated reordering of the radiator-induced displacement damage. Both types of cell were then subjected to several cycles of irradiation and annealing. The results were also very promising. The significant recovery of degraded cell parameters at low temperature might play a major role in considerably extending the end of life of future spacecraft.

  12. Risks and management of radiation exposure.

    PubMed

    Yamamoto, Loren G

    2013-09-01

    High-energy ionizing radiation is harmful. Low-level exposure sources include background, occupational, and medical diagnostics. Radiation disaster incidents include radioactive substance accidents and nuclear power plant accidents. Terrorism and international conflict could trigger intentional radiation disasters that include radiation dispersion devices (RDD) (a radioactive dirty bomb), deliberate exposure to industrial radioactive substances, nuclear power plant sabotage, and nuclear weapon detonation. Nuclear fissioning events such as nuclear power plant incidents and nuclear weapon detonation release radioactive fallout that include radioactive iodine 131, cesium 137, strontium 90, uranium, plutonium, and many other radioactive isotopes. An RDD dirty bomb is likely to spread only one radioactive substance, with the most likely substance being cesium 137. Cobalt 60 and strontium 90 are other RDD dirty bomb possibilities. In a radiation disaster, stable patients should be decontaminated to minimize further radiation exposure. Potassium iodide (KI) is useful for iodine 131 exposure. Prussian blue (ferric hexacyanoferrate) enhances the fecal excretion of cesium via ion exchange. Ca-DTPA (diethylenetriaminepentaacetic acid) and Zn-DTPA form stable ionic complexes with plutonium, americium, and curium, which are excreted in the urine. Amifostine enhances chemical and enzymatic repair of damaged DNA. Acute radiation sickness ranges in severity from mild to lethal, which can be assessed by the nausea/vomiting onset/duration, complete blood cell count findings, and neurologic symptoms. PMID:24201986

  13. Radiation-resistant, amorphous, all-aromatic poly(arylene ether sulfones) - Synthesis, physical behavior, and degradation characteristics

    NASA Technical Reports Server (NTRS)

    Lewis, D. A.; O'Donnell, James H.; Hedrick, J. L.; Ward, T. C.; Mcgrath, J. E.

    1989-01-01

    The effects of Co-60 gamma radiation on a series of poly(arylene ether sulfones) prepared by nucleophilic activated aromatic substitution are investigated experimentally. The preparation of the test compounds is described, and the test results are presented in extensive tables and graphs. Radiation-induced degradation, as measured by SO2 production, was found to be lowest in compounds based on biphenol rather than bisphenol A; these findings were also well correlated with ultimate-tensile-strain measurements.

  14. Phenol Photocatalytic Degradation by Advanced Oxidation Process under Ultraviolet Radiation Using Titanium Dioxide

    PubMed Central

    Nickheslat, Ali; Amin, Mohammad Mehdi; Izanloo, Hassan; Fatehizadeh, Ali; Mousavi, Seyed Mohammad

    2013-01-01

    Background. The main objective of this study was to examine the photocatalytic degradation of phenol from laboratory samples and petrochemical industries wastewater under UV radiation by using nanoparticles of titanium dioxide coated on the inner and outer quartz glass tubes. Method. The first stage of this study was conducted to stabilize the titanium dioxide nanoparticles in anatase crystal phase, using dip-coating sol-gel method on the inner and outer surfaces of quartz glass tubes. The effect of important parameters including initial phenol concentration, TiO2 catalyst dose, duration of UV radiation, pH of solution, and contact time was investigated. Results. In the dip-coat lining stage, the produced nanoparticles with anatase crystalline structure have the average particle size of 30 nm and are uniformly distributed over the tube surface. The removal efficiency of phenol was increased with the descending of the solution pH and initial phenol concentration and rising of the contact time. Conclusion. Results showed that the light easily passes through four layers of coating (about 105 nm). The highest removal efficiency of phenol with photocatalytic UV/TiO2 process was 50% at initial phenol concentration of 30 mg/L, solution pH of 3, and 300 min contact time. The comparison of synthetic solution and petrochemical wastewater showed that at same conditions the phenol removal efficiency was equal. PMID:23710198

  15. Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradation

    NASA Astrophysics Data System (ADS)

    Remec, Igor; Rosseel, Thomas M.; Field, Kevin G.; Le Pape, Yann

    2016-02-01

    Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete, with a particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to ensure reliable risk assessment for extended operation of nuclear power plants. Notice: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC0500OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  16. Acute radiation syndrones and their management

    SciTech Connect

    Cronkite, E.P.

    1988-01-01

    Radiation syndromes produced by large doses of ionizing radiation are divided into three general groups depending on dose of radiation and time after exposure. The CNS syndrome requires many thousands of rad, appears in minutes to hours, and kills within hours to days. The GIS appears after doses of a few hundred to 2000 rad. It is characterized by nausea, vomiting, diarrhea, and disturbances of water and electrolyte metabolism. It has a high mortality in the first week after exposure. Survivors will then experience the HS as a result of marrow aplasia. Depending on dose, survival is possible with antibiotic and transfusion therapy. The relationship of granulocyte depression to mortality in dogs and human beings is illustrated. The role of depth dose pattern of mortality of radiation exposure is described and used as an indication of why air exposure doses may be misleading. The therapy of radiation injury is described based on antibiotics, transfusion therapy, and use of molecular regulators. The limited role of matched allogenic bone marrow transplants is discussed. 52 refs., 13 figs.

  17. A socio-ecological investigation of options to manage groundwater degradation in the Western Desert, Egypt.

    PubMed

    King, Caroline; Salem, Boshra

    2012-07-01

    Under increasing water scarcity, collective groundwater management is a global concern. This article presents an interdisciplinary analysis of this challenge drawing on a survey including 50 large and small farms and gardens in a village in an agricultural land reclamation area on the edge of the Western Desert of Egypt. Findings revealed that smallholders rely on a practice of shallow groundwater use, through which drainage water from adjacent irrigation areas is effectively recycled within the surface aquifer. Expanding agroindustrial activities in the surrounding area are socio-economically important, but by mining non-renewable water in the surrounding area, they set in motion a degradation process with social and ecological consequences for all users in the multi-layered aquifer system. Based on the findings of our investigation, we identify opportunities for local authorities to more systematically connect available environmental information sources and common pool resource management precedents, to counterbalance the degradation threat. PMID:22569842

  18. Evaluation and prediction of the degradation of space Si solar cells induced by a low-earth-orbit radiation environment

    NASA Astrophysics Data System (ADS)

    Gao, Xin; Yang, Sheng-Sheng; Feng, Zhan-Zu; Zhang, Lei

    2012-09-01

    Space-graded silicon solar cells are evaluated by 1 MeV and 2 MeV electron-irradiation. The mean degradation of the maximum power (Pmax) is presented and analyzed. The degradation at both electron energies has been correlated with the displacement damage dose (Dd). A good linearity between the electron Dd and the mean Pmax degradation is obtained. The concept of Dd has also been used to predict the Si solar cell response in a low-earth-orbit (Altitude 799 km, Inclination 99°) radiation environment, considering the shielded effect of a 120 μm-thick silica coverglass on reducing the radiation. Compared with the on-orbit data from a Si solar array of a Chinese satellite (duration from April 2007 to July 2010), a good match can be found between the on-orbit data and the predicted results using Dd methodology, indicating the method is appropriate for evaluating the radiation damage of the solar cells, and also to provide a new technique for studying radiation effects on the optoelectronic detectors used in many high energy physics applications, where harsh radiation environments produce damage in optoelectronic device materials.

  19. [Possibilities and perspectives of quality management in radiation oncology].

    PubMed

    Seegenschmiedt, M H; Zehe, M; Fehlauer, F; Barzen, G

    2012-11-01

    The medical discipline radiation oncology and radiation therapy (treatment with ionizing radiation) has developed rapidly in the last decade due to new technologies (imaging, computer technology, software, organization) and is one of the most important pillars of tumor therapy. Structure and process quality play a decisive role in the quality of outcome results (therapy success, tumor response, avoidance of side effects) in this field. Since 2007 all institutions in the health and social system are committed to introduce and continuously develop a quality management (QM) system. The complex terms of reference, the complicated technical instruments, the highly specialized personnel and the time-consuming processes for planning, implementation and assessment of radiation therapy made it logical to introduce a QM system in radiation oncology, independent of the legal requirements. The Radiation Center Hamburg (SZHH) has functioned as a medical care center under medical leadership and management since 2009. The total QM and organization system implemented for the Radiation Center Hamburg was prepared in 2008 and 2009 and certified in June 2010 by the accreditation body (TÜV-Süd) for DIN EN ISO 9001:2008. The main function of the QM system of the SZHH is to make the basic principles understandable for insiders and outsiders, to have clear structures, to integrate management principles into the routine and therefore to organize the learning processes more effectively both for interior and exterior aspects. PMID:23069993

  20. Radiation-induced failures and degradation of wireless real-time dosimeter under high-dose-rate irradiation

    NASA Astrophysics Data System (ADS)

    Tsuchiya, K.; Kuroki, K.; Akiba, N.; Kurosawa, K.; Matsumoto, T.; Nishiyama, J.; Harano, H.

    2010-04-01

    Radiation-induced malfunction and degradation of electronic modules in certain operating conditions are described in this report. The cumulative radiation effects on Atmel AVR microcontrollers, and 2.4 GHz and 303 MHz wireless network devices were evaluated under gamma ray irradiation with dose rates of 100, 10 and 3 Gy/h. The radiation-induced malfunctions occurred at doses of 510+/-22 Gy for AVR microcontrollers, and 484+/-111 and 429+/-14 Gy for 2.4 GHz and 303 MHz wireless network devices, respectively, under a 100 Gy/h equivalent dose rate. The degradation of microcontrollers occurred for total ionizing doses between 400 and 600 Gy under X-ray irradiation. In addition, we evaluated the reliability of neutron dosimeters using a standard neutron field. One of the neutron dosimeters gave a reading that was half of the standard field value.

  1. Radiation-Related Injuries and Their Management: An Update

    PubMed Central

    Wunderle, Kevin; Gill, Amanjit S.

    2015-01-01

    Ionizing radiation (in the form of X-rays) is used for the majority of procedures in interventional radiology. This review article aimed at promoting safer use of this tool through a better understanding of radiation dose and radiation effects, and by providing guidance for setting up a quality assurance program. To this end, the authors describe different radiation descriptive quantities and their individual strengths and challenges, as well as the biologic effects of ionizing radiation, including patient-related effects such as tissue reactions (previously known as deterministic effects) and stochastic effects. In this article, the clinical presentation, immediate management, and clinical follow-up of these injuries are also discussed. Tissue reactions are important primarily from the patients' perspective, whereas stochastic effects are most relevant for pediatric patients and from an occupational viewpoint. The factors affecting the likelihood of skin reaction (the most common tissue reaction) are described, and how this condition should be managed is discussed. Setting up a robust quality assurance program around radiation dose is imperative for effective monitoring and reduction of radiation exposure to patients and operators. Recommendations for the pre-, peri-, and postprocedure periods are given, including recommendations for follow-up of high-dose cases. Special conditions such as pregnancy and radiation recall are also discussed. PMID:26038622

  2. Some considerations for mass casualty management in radiation emergencies.

    PubMed

    Hopmeier, Michael; Abrahams, Jonathan; Carr, Zhanat

    2010-06-01

    Radiation emergencies are rather new to humankind, as compared to other types of emergencies such as earthquakes, floods, or hurricanes. Fortunately, they are rare, but because of that, planning for response to large-scale radiation emergencies is least understood. Along with the specific technical aspects of response to radiation emergencies, there are some general guiding principles of responding to mass casualty events of any nature, as identified by the World Health Organization in its 2007 manual for mass casualty management systems. The paper brings forward such general considerations as applicable to radiation mass casualty events, including (1) clear lines of communication; (2) scalability of approach; (3) whole-of-health approach; (4) knowledge based approach; and (5) multisectoral approach. Additionally, some key considerations of planning for mass casualty management systems are discussed, namely, health systems surge capacity and networking, risk and resources mapping, and others. PMID:20445382

  3. Uses and Abuses of Models in Radiation Risk Management

    SciTech Connect

    Strom, Daniel J.

    1998-12-10

    This paper is a high-level overview of managing risks to workers, public, and the environment. It discusses the difference between a model and a hypothesis. The need for models in risk assessment is justified, and then it is shown that radiation risk models that are useable in risk management are highly simplistic. The weight of evidence is considered for and against the linear non-threshold (LNT) model for carcinogenesis and heritable ill-health that is currently the basis for radiation risk management. Finally, uses and misuses of this model are considered. It is concluded that the LNT model continues to be suitable for use as the basis for radiation protection.

  4. Effect of radiation-degraded chitosan on plants stressed with vanadium

    NASA Astrophysics Data System (ADS)

    Xuan Tham, Le; Nagasawa, Naotsugu; Matsuhashi, Shinpei; Ishioka, Noriko S.; Ito, Takehito; Kume, Tamikazu

    2001-05-01

    The toxicity of vanadium (V) and the effect of chitosan has been investigated on soybean, rice, wheat and barley. Wheat and barley were sensitive to V than rice and soybean but all seedlings of these plants were damaged at 2.5 μg/ml V (in VCl 3). These damages were reduced by application of radiation-degraded chitosan. The recovery of growth and reduction of V levels in seedlings were obtained by the treatments with 10-100 μg/ml chitosan irradiated at 70-200 kGy of γ-rays in 1% solution. The reductions of V and Fe contents in plants were due to the ability of chitosan to form chelate complexes with metals in solution. The result of BAS analysis shows that the absorption and transportation of 48V to the leaf from root was suppressed with irradiated chitosan. Therefore, it can be concluded that chitosan irradiated at suitable doses (ca. 100 kGy) is effective as plant growth promoters and heavy metal eliminators in crop production.

  5. Exploring the Management of Radiation Proctitis in Current Clinical Practice

    PubMed Central

    Soni, Abhishek; Kaur, Paramjeet; Chauhan, Ashok Kumar; Kaushal, Vivek

    2016-01-01

    Introduction Radiation proctitis is radiation induced rectal mucositis, occurring as a consequence to radiation therapy of the pelvic organs for various pelvic region malignancies. The management of radiation proctitis is extremely challenging as no recommended guidelines are available and limited number of studies are there in the literature involving the various treatment options. Aim The aim of the study is the in-depth review of published literature to see the role of various treatment modalities in the management of radiation proctitis. Materials and Methods An integrative review was undertaken within PubMed, MEDLINE, PMC, GOOGLE SEARCH databases and articles published upto February 2015 were reviewed and analysed. A total of 54 studies were included. Results Literature suggests that non surgical therapies are the first line of treatment and surgery is reserved for advanced or refractory cases. Endoscopic therapies form the mainstay of treatment in managing the patients of radiation proctitis. Argon plasma coagulation and laser therapies are preferred. Radiofrequency ablation, cryoablation and mesenchymal stem cell therapy are the upcoming modalities. Medical therapy can be tried alone or in conjunction to endoscopic therapies. In the resistant or refractory cases, surgery can be looked for in the form of diversion or resection with or without anastamosis. Conclusion Though, a number of options are available, still a lot can be explored in this field to improve the morbidity in the patients and to confirm the superiority of one treatment over other. PMID:27504391

  6. Reaction pathway of the degradation of the p-hydroxybenzoic acid by sulfate radical generated by ionizing radiations

    NASA Astrophysics Data System (ADS)

    Criquet, Justine; Leitner, Nathalie Karpel Vel

    2015-01-01

    The degradation of p-hydroxybenzoic acid (HBA) in aqueous solutions by ionizing radiation was studied. The phenolic pollutant was easily removed by the electron beam irradiation, as more than 80% of the initial 100 μM introduced was degraded for a dose of 600 Gy. It was shown that the addition of persulfate, producing the sulfate radical as additional reactive species, induced a change in the reaction pathway. LC-MS analyses were performed in order to identify the different by-products formed. In the absence of persulfate, the main by-product formed was 3,4-dihydroxybenzoic acid, while in presence of persulfate, 1,4-benzoquinone was detected and the hydroxylated by-products were not present. A reaction pathway of HBA degradation by hydroxyl and sulfate radicals was proposed from the identification of the chemical structure of the different by-products detected. The influences of pH and dissolved oxygen were also studied. A high decline of HBA degradation was observed at pH 11 compared to pH 4.5, this decrease was minimized in the presence of persulfate. The dissolved oxygen concentration was found to be a limiting parameter of HBA degradation, however an excess of dissolved oxygen in solution did not improve the degradation to a large extent.

  7. Proactive Management of Materials Degradation - A Review of Principles and Programs

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Taylor, Theodore T.

    2008-08-28

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundation for defining proactive actions so that future degradation of materials in light water reactors (LWRs) is limited and, thereby, does not diminish either the integrity of important LWR components or the safety of operating plants. This technical letter report was prepared by staff at Pacific Northwest National Laboratory in support of the NRC Proactive Management of Materials Degradation (PMMD) program and relies heavily on work that was completed by Dr. Joseph Muscara and documented in NUREG/CR-6923. This report concisely explains the basic principles of PMMD and its relationship to prognostics, provides a review of programs related to PMMD being conducted worldwide, and provides an assessment of the technical gaps in PMMD and prognostics that need to be addressed. This technical letter report is timely because the majority of the U.S. reactor fleet is applying for license renewal, and many plants are also applying for increases in power rating. Both of these changes could increase the likelihood of materials degradation and underline, therefore, the interest in proactive management in the future.

  8. Stratospheric Aerosols for Solar Radiation Management

    NASA Astrophysics Data System (ADS)

    Kravitz, Ben

    SRM in the context of this entry involves placing a large amount of aerosols in the stratosphere to reduce the amount of solar radiation reaching the surface, thereby cooling the surface and counteracting some of the warming from anthropogenic greenhouse gases. The way this is accomplished depends on the specific aerosol used, but the basic mechanism involves backscattering and absorbing certain amounts of solar radiation aloft. Since warming from greenhouse gases is due to longwave (thermal) emission, compensating for this warming by reduction of shortwave (solar) energy is inherently imperfect, meaning SRM will have climate effects that are different from the effects of climate change. This will likely manifest in the form of regional inequalities, in that, similarly to climate change, some regions will benefit from SRM, while some will be adversely affected, viewed both in the context of present climate and a climate with high CO2 concentrations. These effects are highly dependent upon the means of SRM, including the type of aerosol to be used, the particle size and other microphysical concerns, and the methods by which the aerosol is placed in the stratosphere. SRM has never been performed, nor has deployment been tested, so the research up to this point has serious gaps. The amount of aerosols required is large enough that SRM would require a major engineering endeavor, although SRM is potentially cheap enough that it could be conducted unilaterally. Methods of governance must be in place before deployment is attempted, should deployment even be desired. Research in public policy, ethics, and economics, as well as many other disciplines, will be essential to the decision-making process. SRM is only a palliative treatment for climate change, and it is best viewed as part of a portfolio of responses, including mitigation, adaptation, and possibly CDR. At most, SRM is insurance against dangerous consequences that are directly due to increased surface air

  9. Study of thermal management for space platform applications: Unmanned modular thermal management and radiator technologies

    NASA Technical Reports Server (NTRS)

    Oren, J. A.

    1981-01-01

    Candidate techniques for thermal management of unmanned modules docked to a large 250 kW platform were evaluated. Both automatically deployed and space constructed radiator systems were studied to identify characteristics and potential problems. Radiator coating requirements and current state-of-the-art were identified. An assessment of the technology needs was made and advancements were recommended.

  10. The activation energy of oxidative thermal degradation of radiation- and peroxide-crosslinked low-density polyethylene

    SciTech Connect

    Matusevich, Yu.I.; Butovskaya, G.V.; Krul, L.P.

    1994-11-01

    The parameters of thermal degradation (kinetic order of the reaction, preexponential factor logA, and activation energy E{sub d}) of low-density polyethylene crosslinked by radiation or by dicumyl peroxide were determined from thermogravimetric data processed using the complementarity-based method of {open_quotes}supercorrelations.{close_quotes} The degradation of the polymer was found to obey a first-order rate equation. At mass losses of 10-20%, the parameters logA and E{sub d} were shown to decrease with an increasing degree of crosslinking because of the evolution of low-molecular radiolysis products and the low probability of chain radical processes. In the region of more intense destruction, E{sub d} (as well as logA) increases because the degradation of crosslinked polymer macromolecules requires greater energy consumption.

  11. Enhancement of cellular radiation sensitivity through degradation of Chk1 by the XIAP-XAF1 complex

    PubMed Central

    Kim, Kwang Seok; Heo, Jong-Ik; Choi, Kyu Jin; Bae, Sangwoo

    2014-01-01

    X-linked inhibitor of apoptosis (XIAP) and Chk1 are potential molecular targets in radiotherapy. However, their molecular association in the regulation of radiation sensitivity has been rarely studied. Here, we show that XIAP modulates radiation sensitivity by regulating stability of Chk1 in lung cancer cells. Both Chk1 and XIAP are highly expressed in various lung cancer cells. Overexpression of XIAP increased cell survival following genotoxic treatments by preventing downregulation of Chk1. However, XIAP reversed Chk1-protective activity in the presence of XIAP-associated factor 1 (XAF1) by degrading Chk1 via ubiquitination-dependent proteasomal proteolysis. The XIAP-XAF1 complex-mediated Chk1 degradation also required CUL4A and DDB1. Chk1 or XIAP was associated with DDB1 and CUL4A. Depletion of CUL4A or DDB1 prevented the XIAP-XAF1-mediated Chk1 degradation suggesting involvement of a CUL4A/DDB1-based E3 ubiquitin ligase in the process or its collaboration with XIAP E3 ligase activity. Taken together, our findings show that XIAP plays a dual role in modulation of Chk1 stability and cell viability following IR. In the absence of XAF1, XIAP stabilizes Chk1 under IR with corresponding increase of cell viability. By contrast, when XAF1 is overexpressed, XIAP facilitates Chk1 degradation, which leads to enhancement of radiation sensitivity. This selective regulation of Chk1 stability by XIAP and XAF1 could be harnessed to devise a strategy to modulate radiation sensitivity in lung cancer cells. PMID:25535897

  12. Radiation degradation behavior of chlorine-containing vinyl copolymers. Search for improved electron-beam resists

    SciTech Connect

    Helbert, J.N.; Poindexter, E.H.; Pittman, C.U. Jr.; Chen, C.Y.

    1980-06-01

    Vinyl copolymers with high radiation degradation sensitivity have been synthesized by copolymerizing vinylidene chloride (VDC), CH/sub 2/ = CCl/sub 2/, with methyl methacrylate (MMA), methacrylonitrile, methyl ..cap alpha..-chloroacrylate, and dimethyl itaconate using emulsion techniques. In addition, copolymers of methyl ..cap alpha..-chloroacrylate with methyl methacrylate and poly(..cap alpha..-chloroacrylonitrile) were studied. Introduction of vinylidene chloride into methyl methacrylate polymers caused a sharp increase in G/sub s/ even at relatively low VDC incorporation. Upon 29% VDC incorporation, the G/sub s/ value increased from 1.3 (homopolymer of MMA) to 3.4. G/sub s/ was found to be a linear function of copolymer content for several systems, but G/sub x/ was not. At higher VDC levels, the increase in G/sub s/ was countered by increases in G/sub x/. At lower VDC levels, G/sub x/ was suppressed below the values predicted by a linear G/sub x/ dependence on composition for such systems as VDC/MMA, MCA/MMA, and ..cap alpha..-chloroacrylonitrile/MMA. The VDC/MMA copolymer (29% VDC) gave a sensitivity of 4.0 x 10/sup -5/ C/cm/sup 2/ to electron beam exposure using the 0% unexposed resist thickness loss criterion and is 2 to 3 times more sensitive than PMMA. Poly(..cap alpha..-chloroacrylonitrile) is a negative resist with a sensitivity of 5 x 10/sup -5/ C/cm/sup 2/ using one-micron line images for testing.

  13. Assessment of litter degradation in medicinal plants subjected to ultraviolet-B radiation.

    PubMed

    Agrawal, S B; Kumari, Rima

    2013-07-01

    Litter decomposition is an important component of global carbon budget. Elevated influx of ultraviolet-B radiation (UV-B) as a consequence of depletion of stratospheric ozone (O3) layer may affect litter decomposition directly or/modifying the plant tissue quality. Chemical composition of plant can affect litter decomposition. In the present study, three important medicinal plant species i.e. Acorus calamus, Ocimum sanctum and Cymbopogon citratus were exposed to two levels of supplemental UV-B (sUV and sUV,) during the growth period and examined the changes in leaf quality and degradation of leaf litters. The sUV, treatment (+3.6 kJ m(-2) d(-1)) increased the rate of decomposition by 45% and 31% respectively; in leaf litters from O. sanctum and C. citratus, while no significant effect was noticed in A. calamus leaf litter. Higher accumulation of sclerenchymatous tissue around vascular bundles and increased concentrations of total phenols by 39 mg g(-1) probably lowered the decomposition rate; finding k value: 0.0049 g g(-1) d(-1) in leaf litters of A. calamus. The C/N ratio was increased by 14% at sUV2 in C. citratus, whereas in O. sanctum it decreased by 13.6% after treatment. Results of the present experiment illustrates that firstly UV-B can modify the decomposition rate of leaf litter of test plant species, secondly it can alter the tissue chemistry particularly leaf phenolics, N and P concentrations strongly and thus affecting the decay rate and thirdly UV-B effects on decay rate and leaf chemistry is species specific. PMID:24640251

  14. Risk assessment and management of radiofrequency radiation exposure

    SciTech Connect

    Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

    2013-11-13

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  15. Risk assessment and management of radiofrequency radiation exposure

    NASA Astrophysics Data System (ADS)

    Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

    2013-11-01

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  16. Population of Humic Acid Degrading Microorganisms in Andosols under Different Vegetation Types and Grassland Management Regimens.

    PubMed

    Yanagi, Yukiko; Yoda, Kaori; Ogura, Kazuhiko; Fujitake, Nobuhide

    2008-01-01

    To examine the effect of vegetation type and grassland management regimen on the distribution of humus-degrading microorganisms, populations of humic acid-degrading (HAD) bacteria and fungi at three Andosol sites were investigated using the dilution plate method. Each site had three different vegetation types (Eulalia grassland, bamboo grassland, and coniferous plantations). Among the six grassland sites, two were maintained by burning and the others by cutting. HAD microorganisms were found in all soil samples. Low densities and small percentages of HAD bacteria were detected with no significant differences in the number of bacteria found between different vegetation types and grasslands managed in different ways. In contrast, the densities and percentages of HAD fungi differed according to vegetation type and management regimen. Specifically, the percentages of HAD fungi were significantly higher for burned grasslands. At burned sites, the numbers and percentages of HAD bacteria remained at a consistently low level, and no distinct seasonal changes were observed. In contrast, marked seasonal fluctuations in HAD fungi were detected. The percentages of these fungi remained relatively high between April and December. These fluctuations are likely due to the effects of burning on soil microorganisms. PMID:21558687

  17. Improvement of physico-mechanical, thermomechanical, thermal and degradation properties of PCL/gelatin biocomposites: Effect of gamma radiation

    NASA Astrophysics Data System (ADS)

    Zaman, Haydar U.; Beg, M. D. H.

    2015-04-01

    This research was to study the effects of gelatin content variation and gamma radiation after the 2-ethylhexyl acrylate (EHA) pre-treatment on the foundamental properties of gelatin film laminated polycaprolactone (PCL) biocomposites. PCL/gelatin film (PCL/GF) composites were fabricated by compression molding and their properties were studied by physico-mechanical, thermomechanical, thermal and degradation properties. The results from mechanical properties such as tensile modulus and impact strength of the composites increased with increasing of gelatin content up to 10 wt% and then decreased while the tensile strength and elongation at break decreased. EHA monomer (2-8 wt%) was added to the gelatin solution and films were prepared by casting and found to increase the mechanical properties of the PCL/EHA blended gelatin film (PCL/EGF) composites. Treatment of the gelatin film with gamma radiation after the EHA pre-treatment showed the best mechanical properties of the resulting composites. Dynamic mechanical thermal analysis results showed that the storage modulus of the PCL/EGF and PCL/EHA blended gelatin film with gamma radiation (PCL/GEGF) composites was increased significantly. The degradation properties in water and soil were determined for the non-irradiated and irradiated composites. It was observed that the non-irradiated composite degrades more than that of the irradiated composites.

  18. Medical Management of Acute Radiation Syndromes : Immunoprophylaxis by Antiradiation Vaccine

    NASA Astrophysics Data System (ADS)

    Popov, Dmitri; Maliev, Vecheslav; Jones, Jeffrey; Casey, Rachael; Kedar, Prasad

    Introduction: Traditionally, the treatment of Acute Radiation Syndrome (ARS) includes supportive therapy, cytokine therapy, blood component transfusions and even stem cell transplantation. Recommendations for ARS treatment are based on clinical symptoms, laboratory results, radiation exposure doses and information received from medical examinations. However, the current medical management of ARS does not include immune prophylaxis based on antiradiation vaccines or immune therapy with hyperimmune antiradiation serum. Immuneprophylaxis of ARS could result from stimulating the immune system via immunization with small doses of radiation toxins (Specific Radiation Determinants-SRD) that possess significant immuno-stimulatory properties. Methods: Principles of immuno-toxicology were used to derive this method of immune prophylaxis. An antiradiation vaccine containing a mixture of Hematotoxic, Neurotoxic and Non-bacterial (GI) radiation toxins, underwent modification into a toxoid forms of the original SRD radiation toxins. The vaccine was administered to animals at different times prior to irradiation. The animals were subjected to lethal doses of radiation that induced different forms of ARS at LD 100/30. Survival rates and clinical symptoms were observed in both control and vaccine-treated animals. Results: Vaccination with non-toxic doses of Radiation toxoids induced immunity from the elaborated Specific Radiation Determinant (SRD) toxins. Neutralization of radiation toxins by specific antiradiation antibodies resulted in significantly improved clinical symptoms in the severe forms of ARS and observed survival rates of 60-80% in animals subjected to lethal doses of radiation expected to induce different forms of ARS at LD 100/30. The most effective vaccination schedule for the antiradiation vaccine consisted of repeated injections 24 and 34 days before irradiation. The vaccine remained effective for the next two years, although the specific immune memory probably

  19. The expeditious survey of soils as a management strategy against degradation processes of agroecosystems

    NASA Astrophysics Data System (ADS)

    Machado Siqueira, Glécio; Medeiros Bezerra, Joel

    2013-04-01

    The pressure for agricultural use in hilly areas regarded as marginal to the productive process, committed to carrying capacity of natural systems and exposes the available resources, especially soil and water with higher rates of degradation. This fact, coupled with the lack of planning of production activities, knowing the limitations and capabilities of environmental elements, as well as the use of inappropriate agricultural practices and intensive, quickened the processes that generate environmental imbalance. To circumvent these problems, it is necessary to find mechanisms that mitigate the conflicts generated between productive activities and the environment. One should then respect the specificities and restrictions local soil and their interactions with other components of the environment, trying to select and adapt agricultural practices and techniques best suited to local conditions and enabling the sustainable use of land. For this detailed information and appropriate scale, consistent with the need for rural communities become indispensable instrument to support the management of natural resource use. The expeditious survey of soil provides subsidies to use planning and land management and propose management strategies that ensure higher productivity of soils and maintenance of the environmental quality of the area in question, so as to eliminate or at least alleviate the problems of erosion soil. The joint use of land mapping and topographical and use and occupancy permits integrated management for the recovery of degraded areas, the use of soil conservation practices and indicating areas for reforestation, agriculture and pasture. Thus, this study aims to evaluate the use of GIS tools for improving the expeditious survey of soil. The present study was conducted using data from the municipality of Campo do Meio (Minas Gerais, Brazil). Were prepared soil maps, topography and land use and occupation. Later he was made a map of land use capability (FAO

  20. The degradation of triazo dye chlorantine fast green BLL in aqueous solutions by gamma radiation--III.

    PubMed

    el-Assy, N B; el-Wakeel, E S; Abdel Fattah, A

    1991-01-01

    The radiation degradation yield (Gd values) of Chlorantine Fast Green BLL (CFGBLL), Gd, i.e. the value of moles of dye molecules degraded per joule of energy absorbed (sometimes given in units of the number of molecules decomposed per 100 eV of radiation energy absorbed) was measured in aerated, oxygen- and nitrogen-saturated aqueous solutions. The Gd values were found to be 0.063, 0.0715 and 0.033 mumol/J or (0.61, 0.69 and 0.32/100 eV) respectively. The relatively low degradation yield indicates the absence of chain reactions and probably the poor efficiency and economics, in terms of the practical application of the radiation process. For applications in the radiation treatment of waste water, it is noted that in the presence of oxygen and at higher concentration of CFGBLL, the value of Gd increases markedly, so that it may be practical to monitor the extent of sterilization of water. In addition the radiation processing of CFGBLL waste water may also become economically feasible. The specific bimolecular rate constant of the reaction of CFGBLL with the .OH was determined by studying the effect of ethanol concentration on Gd using competition kinetics. This rate constant was found to be k = 2.32 x 10(10) and 1.65 x 10(10) L mol/s at 610 and 380 nm wavelengths, respectively. Suggestions are made for the possible use of CFGBLL aqueous solution as a chemical dosimeter in the range of absorbed dose from 0.1 to 5 kGy. PMID:1850397

  1. Radiation safety requirements for radioactive waste management in the framework of a quality management system

    SciTech Connect

    Salgado, M.M.; Benitez, J.C.; Pernas, R.; Gonzalez, N.

    2007-07-01

    The Center for Radiation Protection and Hygiene (CPHR) is the institution responsible for the management of radioactive wastes generated from nuclear applications in medicine, industry and research in Cuba. Radioactive Waste Management Service is provided at a national level and it includes the collection and transportation of radioactive wastes to the Centralized Waste Management Facilities, where they are characterized, segregated, treated, conditioned and stored. A Quality Management System, according to the ISO 9001 Standard has been implemented for the RWM Service at CPHR. The Management System includes the radiation safety requirements established for RWM in national regulations and in the Licence's conditions. The role of the Regulatory Body and the Radiation Protection Officer in the Quality Management System, the authorization of practices, training and personal qualification, record keeping, inspections of the Regulatory Body and internal inspection of the Radiation Protection Officer, among other aspects, are described in this paper. The Quality Management System has shown to be an efficient tool to demonstrate that adequate measures are in place to ensure the safety in radioactive waste management activities and their continual improvement. (authors)

  2. Complications of head and neck radiation therapy and their management

    SciTech Connect

    Engelmeier, R.L.; King, G.E.

    1983-04-01

    Patients who receive radiation therapy to the head and neck suffer potential complications and undesirable side-effects of this therapy. The extent of undesirable responses is dependent on the source of irradiation, the fields of irradiation, and the dose. The radiotherapist determines these factors by the extent, location, and radiosensitivity of the tumor. The potential undesirable side-effects are xerostomia, mucositis, fibrosis, trismus, dermatitis, photosensitivity, radiation caries, soft tissue necrosis, and osteoradionecrosis. Each of these clinical entities and their proposed management have been discussed.

  3. Optimal economy-based battery degradation management dynamics for fuel-cell plug-in hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Martel, François; Kelouwani, Sousso; Dubé, Yves; Agbossou, Kodjo

    2015-01-01

    This work analyses the economical dynamics of an optimized battery degradation management strategy intended for plug-in hybrid electric vehicles (PHEVs) with consideration given to low-cost technologies, such as lead-acid batteries. The optimal management algorithm described herein is based on discrete dynamic programming theory (DDP) and was designed for the purpose of PHEV battery degradation management; its operation relies on simulation models using data obtained experimentally on a physical PHEV platform. These tools are first used to define an optimal management strategy according to the economical weights of PHEV battery degradation and the secondary energy carriers spent to manage its deleterious effects. We then conduct a sensitivity study of the proposed optimization process to the fluctuating economic parameters associated with the fuel and energy costs involved in the degradation management process. Results demonstrate the influence of each parameter on the process's response, including daily total operating costs and expected battery lifetime, as well as establish boundaries for useful application of the method; in addition, they provide a case for the relevance of inexpensive battery technologies, such as lead-acid batteries, for economy-centric PHEV applications where battery degradation is a major concern.

  4. Managing Radiation Therapy Side Effects: What to Do about Changes When You Urinate

    MedlinePlus

    ... C ancer I nstitute Managing Radiation Therapy Side Effects What to do about changes when you urinate “ ... drinking enough each day. Managing Radiation Therapy Side Effects: Changes when you urinate Ask about drinks or ...

  5. Management of radiation therapy patients with cardiac defibrillator or pacemaker.

    PubMed

    Salerno, Francesca; Gomellini, Sara; Caruso, Cristina; Barbara, Raffaele; Musio, Daniela; Coppi, Tamara; Cardinale, Mario; Tombolini, Vincenzo; de Paula, Ugo

    2016-06-01

    The increasing growth of population with cardiac implantable electronic devices (CIEDs) such as Pacemaker (PM) and Implantable Cardiac Defibrillators (ICD), requires particular attention in management of patients needing radiation treatment. This paper updates and summarizes some recommendations from different international guidelines. Ionizing radiation and/or electromagnetic interferences could cause device failure. Current approaches to treatment in patients who have these devices vary among radiation oncology centres. We refer to the German Society of Radiation Oncology and Cardiology guidelines (ed. 2015); to the Society of Cardiology Australia and New Zealand Statement (ed. 2015); to the guidelines in force in the Netherlands (ed. 2012) and to the Italian Association of Radiation Oncology recommendations (ed. 2013) as reported in the guidelines for the treatment of breast cancer in patients with CIED. Although there is not a clear cut-off point, risk of device failure increases with increasing doses. Cumulative dose and pacing dependency have been combined to categorize patients into low-, medium- and high-risk groups. Measures to secure patient safety are described for each category. The use of energy ≤6MV is preferable and it's strongly recommended not to exceed a total dose of 2 Gy to the PM and 1 Gy for ICD. Given the dangers of device malfunction, radiation oncology departments should adopt all the measures designed to minimize the risk to patients. For this reason, a close collaboration between cardiologist, radiotherapist and physicist is necessary. PMID:26706454

  6. The changing role of radiation oncology in cancer management

    SciTech Connect

    Brady, L.W.

    1983-06-15

    Radiation therapy has made major contributions to the improved quality of care for the cancer patient. This quality improvement has derived not only from a greater understanding of the natural history of the disease process but also from a more critical evaluation of the results of clinical treatment. Today, clinical radiation therapy stands on a firm foundation of basic understanding of ionizing radiations and its effect on tissue, the biology of the effect in normal tissues and tumor. This explosive growth in knowledge relative to radiation therapy physics, clinical treatment planning, the utilization of computers in radiation therapy as well as basic information in radiation biology and how it might be implemented in clinical situations are well known. Data will be presented to illustrate how major and important applications of basic physics and biologic data in clinical practice are beginning to influence the changing character of cancer management. These new techniques, now being implemented in general clinical practice, offer major potential opportunities toward improving the expectation for cure of many cancers, not cured in the past.

  7. In search of radiation minima for balancing the needs of forest and water management in snow dominated watersheds (Invited)

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Seyednasrollah, B.; Link, T. E.

    2013-12-01

    In upland snowfed forested watersheds, where the majority of melt recharge occurs, there is growing interest among water and forest managers to strike a balance between maximizing forest productivity and minimizing impacts on water resources. Implementation of forest management strategies that involve reduction of forest cover generally result in increased water yield and peak flows from forests, which has potentially detrimental consequences including increased erosion, stream destabilization, water shortages in late melt season, and degradation of water quality and ecosystem health. These ill effects can be partially negated by implementing optimal gap patterns and vegetation densities through forest management, that may minimize net radiation on snow-covered forest floor (NRSF). A small NRSF can moderate peak flows and increase water availability late in the melt season. Since forest canopies reduce direct solar (0.28 - 3.5 μm) radiation but increase longwave (3.5-100 μm) radiation at the snow surface, by performing detailed quantification of individual radiation components for a range of vegetation density and and gap configurations, we identify the optimal vegetation configurations. We also evaluate the role of site location, its topographic setting, local meteorological conditions and vegetation morphological characteristics, on the optimal configurations. The results can be used to assist forest managers to quantify the radiative regime alteration for various thinning and gap-creation scenarios, as a function of latitudinal, topographic, climatic and vegetation characteristics.

  8. 10 Years Evolution Of Cluster Solar Arrays And Forecasting Their Degradation After Entering The Inner Radiation Belt

    NASA Astrophysics Data System (ADS)

    Letor, R.; Marie, J.; Sangiorgi, S.; Volpp, H. J.

    2011-10-01

    The Cluster fleet was launched in 2000 to investigate the interaction between the solar wind and the Earth magnetosphere. Originally operations were planned to end in 2003 but the mission is now approved until end 2014 provided a successful midterm review in 2012. Gravitational perturbations have reduced the perigee altitude of their highly elliptical orbit which caused the spacecraft to periodically fly into the inner radiation belt bringing about significant degradations of the silicon solar cells. Since these degradations cannot be modelled by previous mathematical approaches involving linear extrapolation, a physical model has been developed based on NASA's AP8 radiation belt data, solar cell qualification test results, and an accurate IV-curve model with temperature dependence. This paper presents design characteristics of Cluster solar generators and the evolution of their performance over the past ten years. The modelling of generated solar power is detailed and the output is compared to telemetry in order to explain the observed degradation rate variations, the unexpected power drops around perigee, and forecast available power on-board spacecraft until end 2014.

  9. Land degradation causes and sustainable land management practices in southern Jordan

    NASA Astrophysics Data System (ADS)

    Khresat, Saeb

    2014-05-01

    Jordan is one of the world's most water-deficit countries with only about 4% of the total land area considered arable. As a consequence agricultural production is greatly constrained by limited natural resources. Therefore, a major challenge for the country is to promote the sustainable use of natural resources for agricultural purposes. This challenge is being made harder by the ongoing processes of degradation due to increased population pressure, which undermine any social and economic development gains. In the southern plains of Jordan, sustainability of farming practices has worsened in the past three decades, exacerbating pressure on land and increasing land degradation processes. Non-sustainable land use practices include improper ploughing, inappropriate rotations, inadequate or inexistent management of plant residues, overgrazing of natural vegetation, random urbanization, land fragmentation and over-pumping of groundwater. The root cause is the high population growth which exerts excessive pressure on the natural resources to meet increased food and income demand. The poorest farmers who are increasingly growing cereals on marginal areas. Wheat and barley are now grown with little to no rotation, with no nutrient replenishment, and at places avoiding even fallow. Small landholding sizes and topographic features of the area tend to oblige longitudinal mechanized tillage operations along the slopes. Overall, the constraints facing the deprived land users such as, poor access to technology, capital and organization are the factors that lead into unsustainable practices. The main bottlenecks and barriers that hinder mainstreaming of sustainable land management in Jordan can be grouped into three main categories: (i) Knowledge, (ii) Institutional and Governance, and (iii) Economic and Financial. In this case study, the key challenge was to create a knowledge base among local stakeholders - including planners, extension officers, NGO/community leaders, teachers

  10. Martian Analogue Samples, Their Spectroscopic Biosignatures, and Degradation by the Cosmic Radiation Environment

    NASA Astrophysics Data System (ADS)

    Dartnell, L. R.

    2016-05-01

    Here we discuss the use of Raman and FTIR spectroscopy for the detection and characterisation of biosignatures in martian analogue samples, and their degradation by the cosmic ray environment in the martian near-subsurface.

  11. Medical management of three workers following a radiation exposure incident

    SciTech Connect

    House, R.A.; Sax, S.E.; Rumack, E.R.; Holness, D.L. )

    1992-01-01

    The medical management of three individuals involved in an exposure incident to whole-body radiation at a nuclear generating plant of a Canadian electrical utility is described. The exposure incident resulted in the two highest whole-body radiation doses ever received in a single event by workers in a Canadian nuclear power plant. The individual whole-body doses (127.4 mSv, 92.0 mSv, 22.4 mSv) were below the threshold for acute radiation sickness but the exposures still presented medical management problems related to assessment and counseling. Serial blood counting and lymphocyte cytogenetic analysis to corroborate the physical dosimetry were performed. All three employees experienced somatic symptoms due to stress and one employee developed post-traumatic stress disorder. This incident indicates that there is a need in such radiation exposure accidents for early and continued counseling of exposed employees to minimize the risk of development of stress-related symptoms.

  12. Radiation therapy in the management of patients with mesothelioma

    SciTech Connect

    Gordon, W. Jr.; Antman, K.H.; Greenberger, J.S.; Weichselbaum, R.R.; Chaffey, J.T.

    1982-01-01

    The results of radiation therapy in the management of 27 patients with malignant mesothelioma were reviewed. Eight patients were treated with a curative intent combining attempted surgical excision of tumor (thoracic in 6 and peritoneal in 2), aggressive radiation therapy, and combination chemotherapy using an adriamycin-containing regimen. One patient achieved a 2-year disease-free inteval followed by recurrence of tumor above the thoracic irradiation field. This patient was retreated with localized irradiation and is disease-free after 5 years of initial diagnosis. One patient has persistent abdominal disease at 18 months; the other 6 patients suffered local recurrence within 8-13 months of initiation of treatment. Radiation therapy was used in 19 other patients who received 29 courses for palliation of dyspnea, superior vena cava syndrome, dysphagia, or neurological symptoms of brain metastasis. A palliation index was used to determine the effectiveness of irradiation and revealed that relief of symptoms was complete or substantial in 5 treatment courses, moderately effective in 6 courses and inadequate in 18 treatment courses. Adequate palliation strongly correlated with a dose at or above 4,000 rad in 4 weeks. The management of patients with mesothelioma requires new and innovative approaches to increase the effectiveness of radiation therapy and minimize the significant potential combined toxicity of pulmonary irradiation and adriamycin.

  13. Compton Radiation for Nuclear Waste Management and Transmutation

    NASA Astrophysics Data System (ADS)

    Bulyak, E.; Urakawa, J.

    2015-10-01

    Compton inverse radiation is emitted in the process of backscattering of the laser pulses off the relativistic electrons. This radiation possesses high spectral density and high energy of photons--in hard x-ray up to gammaray energy range--with moderate electron energies (hundreds of MeV up to 1 GeV) due to short wavelength of the laser radiation. The Compton radiation is well collimated: emitting within a narrow cone along the electron beam. A distinct property of the Compton inverse radiation is a steep high-energy cutoff of the spectrum and the maximal intensity just below the cutoff. The Compton sources can attain: spectral density up to 1014 gammas/(s 0.1%bandwidth) in MeV range of energies, and spectral brightness up to 1020 gammas/(smm2mr2 0.1% bw). Applicability of Compton sources for nuclear waste management and detection of radioisotopes and fissionable nuclides are discussed in the report. Also application limits of Compton gamma sources for transmutation of radioactive isotopes are estimated. A recently proposed subtracting method, in which two sets of data obtained by irradiating the object by the Compton beams with slightly different maximal energies are compared, will enhance resolution of detection radioactive elements at the 'atomic' (hundreds of keV) and the 'nuclear' (a few MeV) photon energies.

  14. Solar Radiation Management and Olivine Dissolution Methods in Climate Engineering

    NASA Astrophysics Data System (ADS)

    Kone, S.

    2014-12-01

    An overview of solar radiation management and olivine dissolution methods allows to discuss, comparatively, the benefits and consequences of these two geoengineering techniques. The combination of those two techniques allows to concomitantly act on the two main agents intervening in global warming: solar radiation and carbon dioxide. The earth surface temperature increases due mainly to carbon dioxide (a greenhouse gas) that keeps the solar radiation and causes the global warming. Two complementary methods to mitigate climate change are overviewed: SRM method, which uses injected aerosols, aims to reduce the amount of the inbound solar radiation in atmosphere; and olivine dissolution in water, a key chemical reaction envisaged in climate engineering , aiming to reduce the amount of the carbon dioxide in extracting it from atmosphere. The SRM method works on scenarios of solar radiation decrease and the olivine dissolution method works as a carbon dioxide sequestration method. Olivine dissolution in water impacts negatively on the pH of rivers but positively in counteracting ocean acidification and in transporting the silica in ocean, which has benefits for diatom shell formation.

  15. Gamma radiation/H2O2 treatment of a nonylphenol ethoxylates: Degradation, cytotoxicity, and mutagenicity evaluation.

    PubMed

    Iqbal, Munawar; Bhatti, Ijaz Ahmad

    2015-12-15

    Gamma radiation/H2O2 treatment of nonylphenol polyethoxylates (NPEO) was performed and treatment effect was evaluated on the basis of degradation, chemical oxygen demand (COD) and total organic carbon (TOC), and toxicity reduction efficiencies. The radiolytic by-products were determined by Fourier Transform Infrared Spectroscopy (FTIR), High-Performance Liquid Chromatography (HPLC), and Gas Chromatography-Mass Spectrometry (GC-MS) techniques. Low mass carboxylic acids, aldehyde, ketone, and acetic acid were identified as the by-products of the NPEO degradation. NPEO sample irradiated to the absorbed dose of 15 kGy/4.58% H2O2 showed more than 90% degradation. Allium cepa (A. cepa), brine shrimp, heamolytic tests were used for cytotoxicity study, while mutagenicity was evaluated through Ames test (TA98 and TA100 strains) of treated and un-treated NPEO. The reductions in COD and TOC were greater than 70% and 50%, respectively. Gamma radiation/H2O2 treatment revealed a considerable reduction in cytotoxicity and mutagenicity. A. cepa, heamolytic and shrimp assays showed cytotoxicity reduction up to 68.65%, 77%, and 94%, respectively. The mutagenicity reduced up to 62%, 74%, and 79% (TA98) and 68%, 78%, and 82% (TA100), respectively of NPEO-6, NPEO-9, and NPEO-30 irradiated to the absorbed dose of 15 kGy/4.58% H2O2. NPEO-6 detoxified more efficiently versus NPEO-9 and NPEO-30 and results showed that Gamma radiation/H2O2 treatment has the potential to mineralize and detoxify NPEO. PMID:26143198

  16. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya

    NASA Astrophysics Data System (ADS)

    Mganga, K. Z.; Musimba, N. K. R.; Nyariki, D. M.

    2015-12-01

    Drylands occupy more than 80 % of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems.

  17. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya.

    PubMed

    Mganga, K Z; Musimba, N K R; Nyariki, D M

    2015-12-01

    Drylands occupy more than 80% of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems. PMID:26178534

  18. Corporate Functional Management Evaluation of the LLNL Radiation Safety Organization

    SciTech Connect

    Sygitowicz, L S

    2008-03-20

    A Corporate Assess, Improve, and Modernize review was conducted at Lawrence Livermore National Laboratory (LLNL) to evaluate the LLNL Radiation Safety Program and recommend actions to address the conditions identified in the Internal Assessment conducted July 23-25, 2007. This review confirms the findings of the Internal Assessment of the Institutional Radiation Safety Program (RSP) including the noted deficiencies and vulnerabilities to be valid. The actions recommended are a result of interviews with about 35 individuals representing senior management through the technician level. The deficiencies identified in the LLNL Internal Assessment of the Institutional Radiation Safety Program were discussed with Radiation Safety personnel team leads, customers of Radiation Safety Program, DOE Livermore site office, and senior ES&H management. There are significant issues with the RSP. LLNL RSP is not an integrated, cohesive, consistently implemented program with a single authority that has the clear roll and responsibility and authority to assure radiological operations at LLNL are conducted in a safe and compliant manner. There is no institutional commitment to address the deficiencies that are identified in the internal assessment. Some of these deficiencies have been previously identified and corrective actions have not been taken or are ineffective in addressing the issues. Serious funding and staffing issues have prevented addressing previously identified issues in the Radiation Calibration Laboratory, Internal Dosimetry, Bioassay Laboratory, and the Whole Body Counter. There is a lack of technical basis documentation for the Radiation Calibration Laboratory and an inadequate QA plan that does not specify standards of work. The Radiation Safety Program lack rigor and consistency across all supported programs. The implementation of DOE Standard 1098-99 Radiological Control can be used as a tool to establish this consistency across LLNL. The establishment of a site

  19. Radiation-induced and sonochemical degradation of chitosan as a way to increase its fat-binding capacity

    NASA Astrophysics Data System (ADS)

    Czechowska-Biskup, R.; Rokita, B.; Ulanski, P.; Rosiak, J. M.

    2005-07-01

    Three physical methods of chitosan degradation: irradiation in dry state, irradiation in aqueous solution and sonication in aqueous solution were tested and compared in the terms of yields and side effects. The influence of average molecular weight of chitosan in its fat-binding ability in vitro has been studied by using a biopharmaceutical model of digestive tract. It was found that reduction in molecular weight leads to a significant increase in the amount of fat bound by 1 g of chitosan. Thus, radiation- or sonochemical treatment may be useful in improving fat-binding properties of chitosan as an active component of dietary food additives.

  20. Improved management of winter operations to limit subsurface contamination with degradable deicing chemicals in cold regions.

    PubMed

    French, Helen K; van der Zee, Sjoerd E A T M

    2014-01-01

    This paper gives an overview of management considerations required for better control of deicing chemicals in the unsaturated zone at sites with winter maintenance operations in cold regions. Degradable organic deicing chemicals are the main focus. The importance of the heterogeneity of both the infiltration process, due to frozen ground and snow melt including the contact between the melting snow cover and the soil, and unsaturated flow is emphasised. In this paper, the applicability of geophysical methods for characterising soil heterogeneity is considered, aimed at modelling and monitoring changes in contamination. To deal with heterogeneity, a stochastic modelling framework may be appropriate, emphasizing the more robust spatial and temporal moments. Examples of a combination of different field techniques for measuring subsoil properties and monitoring contaminants and integration through transport modelling are provided by the SoilCAM project and previous work. Commonly, the results of flow and contaminant fate modelling are quite detailed and complex and require post-processing before communication and advising stakeholders. The managers' perspectives with respect to monitoring strategies and challenges still unresolved have been analysed with basis in experience with research collaboration with one of the case study sites, Oslo airport, Gardermoen, Norway. Both scientific challenges of monitoring subsoil contaminants in cold regions and the effective interaction between investigators and management are illustrated. PMID:24281673

  1. Endobronchial radiation therapy (EBRT) in the management of lung cancer

    SciTech Connect

    Roach, M. III; Leidholdt, E.M. Jr.; Tatera, B.S.; Joseph, J. )

    1990-06-01

    Between October 1987 and November 1988, 19 endobronchial Iridium-192 line source placements were attempted in 17 patients with advanced incurable lung cancer. Approximately 30 Gy was delivered to the endobronchus using a low dose rate (LDR) afterloading technique delivering a mean dose of 70 cGy/hr at 5 mm. Improvement in subjective symptoms was noted in 67% of evaluable patients whereas objective responses defined by chest X ray and bronchoscopy were noted in 26% and 60%, respectively. No significant morbidity was observed. The radiation exposure to health care workers was low ranging from 10 to 40 mRem per treatment course with most of the staff receiving less than 10 mRem per treatment course (minimal detectable level 10 mRem). The results of this series are compared with selected series using low dose rate as well as intermediate dose rate (IDR) and high dose rate (HDR) endobronchial radiation therapy (EBRT). Based on bronchoscopic responses from the selected series reviewed, both HDR low total dose per treatment (range 7.5-10 Gy) and LDR high total dose per treatment (range 30-50 Gy) are effective in palliating the vast majority of patients with endobronchial lesions. Intermediate dose rate is also effective using fractions similar to high dose rate but total dose similar to low dose rate. The efficacy of endobronchial radiation therapy in the palliative setting suggest a possible role for endobronchial radiation therapy combined with external beam irradiation with or without chemotherapy in the initial management of localized lung cancer. Defining the optimal total dose, dose rate, and the exact role of endobronchial radiation therapy in the management of lung cancer will require large cooperative trials with standardization of techniques and definitions.

  2. Some Properties of Poly(Methyl Methacrylate) Studied by Radiation Degradation: An Interdisciplinary Student Experiment.

    ERIC Educational Resources Information Center

    Hill, D. J. T.; O'Donnell, J. H.

    1981-01-01

    Describes an interdisciplinary student experiment based upon the radiation effects on polymers, integrating some of the fundamentals of radiation chemistry, polymer chemistry, and material science. Also demonstrates how the information gained in the experiment has direct commercial application in product manufacture or processing. (CS)

  3. Radiation Therapy for the Management of Brain Metastases.

    PubMed

    Garrett, Matthew D; Wu, Cheng-Chia; Yanagihara, Ted K; Jani, Ashish; Wang, Tony J C

    2016-08-01

    Brain metastases are the most common malignant intracranial tumors and carry a poor prognosis. The management of brain metastases may include a variety of treatment modalities including surgical resection, radiation therapy, and/or systemic therapy. The traditional treatment for brain metastasis involved whole brain irradiation. However, improved systemic control of primary cancers has led to longer survival for some groups of patients and there is increasing need to consider the late effects of radiation to the entire brain. With advances in imaging and radiation treatment planning and delivery stereotactic radiosurgery has become more frequently utilized and may be delivered through Gamma Knife Stereotactic Radiosurgery or linear accelerator-based systems. Furthermore, experience in treating thousands of patients on clinical trials has led to diagnosis-specific prognostic assessment systems that help guide our approach to the management of this common clinical scenario. This review provides an overview of the literature supporting radiotherapy for brain metastasis and an update on current radiotherapeutic options that is tailored for the nonradiation oncologist. PMID:27213494

  4. Comparison of radiation-induced transmission degradation of borosilicate crown optical glass from four different manufacturers

    NASA Astrophysics Data System (ADS)

    Gusarov, Andrei; Doyle, Dominic; Glebov, Leonid; Berghmans, Francis

    2005-09-01

    Space-born optical systems must be tolerant to radiation to guarantee that the required system performance is maintained during prolonged mission times. The radiation-induced absorption in optical glasses is often related with the presence of impurities, which are, intentionally or not, introduced during the manufacturing process. Glass manufacturers use proprietary fabrication processes and one can expect that the radiation sensitivity of nominally identical optical glasses from different manufacturers is different. We studied the gamma-radiation induced absorption of several crown glasses with nd ≈ 1.516 and vd ≈ 64, i.e. NBK7 (Schott), S-BSL7 (Ohara), BSC 517642 (Pilkington) and K8 (Russia). NBK7 recently replaced the well-known BK7. We therefore also compared the radiation response of NBK7 and BK7 glass. Our results show that whereas the glasses are optically similar before irradiation, they show a different induced absorption after irradiation and also different post-radiation recovery kinetics. Taking these differences into account can help to improve the radiation tolerance of optical systems for space applications.

  5. Image-guided radiation therapy in lymphoma management

    PubMed Central

    Eng, Tony

    2015-01-01

    Image-guided radiation therapy (IGRT) is a process of incorporating imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), Positron emission tomography (PET), and ultrasound (US) during radiation therapy (RT) to improve treatment accuracy. It allows real-time or near real-time visualization of anatomical information to ensure that the target is in its position as planned. In addition, changes in tumor volume and location due to organ motion during treatment can be also compensated. IGRT has been gaining popularity and acceptance rapidly in RT over the past 10 years, and many published data have been reported on prostate, bladder, head and neck, and gastrointestinal cancers. However, the role of IGRT in lymphoma management is not well defined as there are only very limited published data currently available. The scope of this paper is to review the current use of IGRT in the management of lymphoma. The technical and clinical aspects of IGRT, lymphoma imaging studies, the current role of IGRT in lymphoma management and future directions will be discussed. PMID:26484299

  6. Research study on high energy radiation effect and environment solar cell degradation methods

    NASA Technical Reports Server (NTRS)

    Horne, W. E.; Wilkinson, M. C.

    1974-01-01

    The most detailed and comprehensively verified analytical model was used to evaluate the effects of simplifying assumptions on the accuracy of predictions made by the external damage coefficient method. It was found that the most serious discrepancies were present in heavily damaged cells, particularly proton damaged cells, in which a gradient in damage across the cell existed. In general, it was found that the current damage coefficient method tends to underestimate damage at high fluences. An exception to this rule was thick cover-slipped cells experiencing heavy degradation due to omnidirectional electrons. In such cases, the damage coefficient method overestimates the damage. Comparisons of degradation predictions made by the two methods and measured flight data confirmed the above findings.

  7. The effect of simulated low earth orbit radiation on polyimides (UV degradation study)

    NASA Technical Reports Server (NTRS)

    Forsythe, John S.; George, Graeme A.; Hill, David J. T.; Odonnell, James H.; Pomery, Peter J.; Rasoul, Firas A.

    1995-01-01

    UV degradation of polyimide films in air and vacuum were studied using UV-visible, ESR, FTIR, and XPS spectroscopies. The UV-visible spectra of polyimide films showed a blue shift in the absorption compared to Kapton. This behavior was attributed to the presence of bulky groups and kinks along the polymer chains which disrupt the formation of a charge transfer complex. The UV-visible spectra showed also that UV irradiation of polyimides result extensively in surface degradation, leaving the bulk of the polymer intact. ESR spectra of polyimides irradiated in vacuum revealed the formation of stable carbon-centered radicals which give a singlet ESR spectrum, while polyimides irradiated in air produced an asymmetric signal shifted to a lower magnetic field, with a higher g value and line width. This signal was attributed to oxygen-cenetered radicals of peroxy and/or alkoxy type. The rate of radical formation in air was two fold higher than for vacuum irradiation, and reached a plateau after a short time. This suggests a continuous depletion of radicals on the surface via an ablative degradation process. FTIR, XPS, and weight loss studies supported this postulate. An XPS study of the surface indicated a substantial increase in the surface oxidation after irradiation in air. The sharp increase in the C-O binding energy peak relative to the C-C peak was believed to be associated with an aromatic ring opening reaction.

  8. Bacterial and fungal communities in a degraded ombrotrophic peatland undergoing natural and managed re-vegetation.

    PubMed

    Elliott, David R; Caporn, Simon J M; Nwaishi, Felix; Nilsson, R Henrik; Sen, Robin

    2015-01-01

    The UK hosts 15-19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare peat

  9. Bacterial and Fungal Communities in a Degraded Ombrotrophic Peatland Undergoing Natural and Managed Re-Vegetation

    PubMed Central

    Elliott, David R.; Caporn, Simon J. M.; Nwaishi, Felix; Nilsson, R. Henrik; Sen, Robin

    2015-01-01

    The UK hosts 15–19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare

  10. A soil-based framework for integrating and applying knowledge of land degradation proceses to assessment, monitoring and management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe a soil-based framework for organizing, synthesizing, and applying our growing understanding of land degradation processes to assessment, monitoring, and management. The framework is dual-purpose: (1) coordinate the use of existing tools, resources, and knowledge, and (2) facilitate the i...

  11. Forage Management Effects on Protein and Fiber Fractions, Protein Degradability, and Dry Matter Yield of Red Clover Conserved as Silage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the action of o-quinones formed via polyphenol oxidase, conserved red clover (Trifolium pratense L.) contains abundant rumen undegradable protein (RUP), but inadequate rumen degradable protein (RDP) for dairy cattle. This study examined how forage management influences RDP, RUP, crude protein...

  12. Management of oral disease prior to radiation therapy.

    PubMed

    Schiødt, Morten; Hermund, Niels Ulrich

    2002-01-01

    Radiation therapy for malignant tumors of the head and neck is associated with significant side effects involving the oral cavity. For example, radiation therapy leads to reduced vascularity and oxygen tension of the oral hard and soft tissues and also to salivary gland dysfunction. These changes increase the risk of dental decay and oral infections and lead to reduced healing capacity following oral surgery procedures. A severe complication of radiation therapy is osteoradionecrosis of the jaw bone. The purpose of this paper is to review preradiation oral examination and treatment. Patient management regarding oral disease prior to radiation therapy has to accomplish a number of goals: (1) to identify existing oral disease and potential risk of oral disease, (2) to remove infectious dental/oral foci before the start of radiation therapy, (3) to prepare the patient for the expected side effects with information about them, (4) to establish an adequate standard of oral hygiene to meet the increased challenge, (5) to provide a plan for maintaining oral hygiene and fluoride treatment, for oral rehabilitation, and for follow-up and (6) to inform the patient about the availability of any financial support for dental treatment, and finally (7) to establish the necessary multidiciplinary collaboration within the health care system so that oral symptoms and sequelae before, during and after the radiation therapy can be reduced or alleviated. The methods used to accomplish these goals may vary between cancer centers. Each center should have a multidisciplinary team to handle such problems. After the end of radiation therapy most of the dental treatments in our patients are done by private dentists, except for some oral surgery procedures, which are performed in hospital. In our experience, the major challenge in this process is related to (1) informing of the patient, (2) timing the coordination between all the health care workers involved, (3) establishing an adequate

  13. Material Aging and Degradation Detection and Remaining Life Assessment for Plant Life Management

    SciTech Connect

    Ramuhalli, Pradeep; Henager, Charles H.; Griffin, Jeffrey W.; Meyer, Ryan M.; Coble, Jamie B.; Pitman, Stan G.; Bond, Leonard J.

    2012-12-31

    One of the major factors that may impact long term operations is structural material degradation, Detecting materials degradation, estimating the remaining useful life (RUL) of the component, and determining approaches to mitigating the degradation are important from the perspective of long term operations. In this study, multiple nondestructive measurement and monitoring methods were evaluated for their ability to assess the material degradation state. Metrics quantifying the level of damage from these measurements were defined, and evaluated for their ability to provide estimates of remaining life of the component. An example of estimating the RUL from nondestructive measurements of material degradation condition is provided.

  14. Role of radiation therapy in lung cancer management - a review.

    PubMed

    Shi, J-G; Shao, H-J; Jiang, F-E; Huang, Y-D

    2016-07-01

    Lung cancer is the leading cause of cancer death worldwide. Furthermore, more than 50% of lung cancer patients are found affected by distant metastases at the time of diagnosis. On the other hand, 20% of these patients are without regional spread and are good candidates for surgical operation. The remaining 30% represent an intermediate group whose tumors have metastasized up to regional lymph nodes. These remain 30% are the most appropriate candidates for radiation therapy. These patients are also called as "locally advanced lung cancer" or stage III lung cancer patients. In these patients strategy of combination therapy viz. radiation therapy in combination with chemotherapy is also tried by various groups in the recent past for this better management. However, long-term survival is still poor with a 5-year survival in 5-25% of patients. During the last decades, there has been a development in radiation strategies. The present review article focuses on different approaches to optimize radiotherapy for these patients. PMID:27466995

  15. Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

    NASA Technical Reports Server (NTRS)

    Shih, K. L.; Souza, K. A.

    1978-01-01

    The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

  16. Damage Assessment Technologies for Prognostics and Proactive Management of Materials Degradation (PMMD)

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Griffin, Jeffrey W.; Hull, Amy B.; Malik, Shah

    2009-01-16

    There are approximately 440 operating reactors in the global nuclear power plant (NPP) fleet with an average age greater than 20 years and design lives of 30 or 40 years. The United States is currently implementing license extensions of 20 years on many plants, and consideration is now being given to the concept of "life-beyond-60", license extension from 60 to 80 years and potentially longer. In almost all countries with NPPs, authorities are looking at some form of license renewal program. In support of NPP license renewal over the past decade, various national and international programs have been initiated. This paper discusses stressor-based prognostics and its role as part of emerging trends in Proactive Management of Materials Degradation (PMMD) applied to nuclear power plant structures, systems and components (SSC). The paper concisely explains the US Nuclear Regulatory Commission’s (NRC) program in PMMD, the basic principles of PMMD and its relationship to advanced diagnostics and prognostics. It then provides an assessment of the state of maturity for diagnostic and prognostic technologies, including NDE and related technologies for damage assessment, and the current trend to move from condition-based maintenance to on-line monitoring for advanced diagnostics and stressor-based prognostics. This development in technology requires advances in sensors; better understanding of what and how to measure within a nuclear power plant; enhanced data interrogation, communication and integration; new prediction models for damage/aging evolution; system integration for real-world deployments and quantification of uncertainties in what are inherently ill-posed problems. Stressor-based analysis is based upon understanding which stressor characteristics (e.g., pressure transients) provide a percussive indication that can be used for mapping subsequent damage due to a specific degradation mechanism. The resulting physical damage and the associated decrease in asset

  17. Parathyroid Hormone Therapy Mollifies Radiation-Induced Biomechanical Degradation in Murine Distraction Osteogenesis

    PubMed Central

    Deshpande, Sagar S.; Gallagher, Katherine K.; Donneys, Alexis; Tchanque-Fossuo, Catherine N.; Sarhaddi, Deniz; Nelson, Noah S.; Chepeha, Douglas B.; Buchman, Steven R.

    2015-01-01

    Objective Descriptions of mandibular distraction osteogenesis for tissue replacement after oncologic resection or for defects caused by osteoradionecrosis have been limited. Previous work demonstrated radiation decreases union formation, cellularity and mineral density in mandibular distraction osteogenesis. The authors posit that intermittent systemic administration of parathyroid hormone will serve as a stimulant to cellular function, reversing radiation-induced damage and enhancing bone regeneration. Methods Twenty male Lewis rats were randomly assigned to three groups: group 1 (radiation and distraction osteogenesis, n = 7) and group 2 (radiation, distraction osteogenesis, and parathyroid hormone, n = 5) received a human-equivalent dose of 35 Gy of radiation (human bioequivalent, 70 Gy) fractionated over 5 days. All groups, including group 3 (distraction osteogenesis, n = 8), underwent a left unilateral mandibular osteotomy with bilateral external fixator placement. Distraction osteogenesis was performed at a rate of 0.3 mm every 12 hours to reach a gap of 5.1 mm. Group 2 was injected with parathyroid hormone (60 μg/kg) subcutaneously daily for 3 weeks after the start of distraction osteogenesis. On postoperative day 40, all left hemimandibles were harvested. Biomechanical response parameters were generated. Statistical significance was considered at p ≤ 0.05. Results Parathyroid hormone–treated mandibles had significantly higher failure load and higher yield than did untreated mandibles. However, these values were still significantly lower than those of nonirradiated mandibles. Conclusions The authors have successfully demonstrated the therapeutic efficacy of parathyroid hormone to stimulate and enhance bone regeneration in their irradiated murine mandibular model of distraction osteogenesis. Anabolic regimens of parathyroid hormone, a U.S. Food and Drug Administration–approved drug on formulary, significantly improve outcomes in a model of

  18. Esophageal cancer management controversies: Radiation oncology point of view.

    PubMed

    Tai, Patricia; Yu, Edward

    2014-08-15

    Esophageal cancer treatment has evolved from single modality to trimodality therapy. There are some controversies of the role, target volumes and dose of radiotherapy (RT) in the literature over decades. The present review focuses primarily on RT as part of the treatment modalities, and highlight on the RT volume and its dose in the management of esophageal cancer. The randomized adjuvant chemoradiation (CRT) trial, intergroup trial (INT 0116) enrolled 559 patients with resected adenocarcinoma of the stomach or gastroesophageal junction. They were randomly assigned to surgery plus postoperative CRT or surgery alone. Analyses show robust treatment benefit of adjuvant CRT in most subsets for postoperative CRT. The Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) used a lower RT dose of 41.4 Gray in 23 fractions with newer chemotherapeutic agents carboplatin and paclitaxel to achieve an excellent result. Target volume of external beam radiation therapy and its coverage have been in debate for years among radiation oncologists. Pre-operative and post-operative target volumes are designed to optimize for disease control. Esophageal brachytherapy is effective in the palliation of dysphagia, but should not be given concomitantly with chemotherapy or external beam RT. The role of brachytherapy in multimodality management requires further investigation. On-going studies of multidisciplinary treatment in locally advanced cancer include: ZTOG1201 trial (a phase II trial of neoadjuvant and adjuvant CRT) and QUINTETT (a phase III trial of neoadjuvant vs adjuvant therapy with quality of life analysis). These trials hopefully will shed more light on the future management of esophageal cancer. PMID:25132924

  19. Esophageal cancer management controversies: Radiation oncology point of view

    PubMed Central

    Tai, Patricia; Yu, Edward

    2014-01-01

    Esophageal cancer treatment has evolved from single modality to trimodality therapy. There are some controversies of the role, target volumes and dose of radiotherapy (RT) in the literature over decades. The present review focuses primarily on RT as part of the treatment modalities, and highlight on the RT volume and its dose in the management of esophageal cancer. The randomized adjuvant chemoradiation (CRT) trial, intergroup trial (INT 0116) enrolled 559 patients with resected adenocarcinoma of the stomach or gastroesophageal junction. They were randomly assigned to surgery plus postoperative CRT or surgery alone. Analyses show robust treatment benefit of adjuvant CRT in most subsets for postoperative CRT. The Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) used a lower RT dose of 41.4 Gray in 23 fractions with newer chemotherapeutic agents carboplatin and paclitaxel to achieve an excellent result. Target volume of external beam radiation therapy and its coverage have been in debate for years among radiation oncologists. Pre-operative and post-operative target volumes are designed to optimize for disease control. Esophageal brachytherapy is effective in the palliation of dysphagia, but should not be given concomitantly with chemotherapy or external beam RT. The role of brachytherapy in multimodality management requires further investigation. On-going studies of multidisciplinary treatment in locally advanced cancer include: ZTOG1201 trial (a phase II trial of neoadjuvant and adjuvant CRT) and QUINTETT (a phase III trial of neoadjuvant vs adjuvant therapy with quality of life analysis). These trials hopefully will shed more light on the future management of esophageal cancer. PMID:25132924

  20. Degradation of Methyl Orange and Congo Red dyes by using TiO2 nanoparticles activated by the solar and the solar-like radiation.

    PubMed

    Ljubas, Davor; Smoljanić, Goran; Juretić, Hrvoje

    2015-09-15

    In this study we used TiO2 nanoparticles as semiconductor photocatalysts for the degradation of Methyl Orange (MO) and Congo Red (CR) dyes in an aqueous solution. Since TiO2 particles become photocatalytically active by UV radiation, two sources of UV-A radiation were used - natural solar radiation which contains 3-5% UV-A and artificial, solar-like radiation, created by using a lamp. The optimal doses of TiO2 of 500 mg/L for the CR and 1500 mg/L for the MO degradation were determined in experiments with the lamp and were also used in degradation experiments with natural solar light. The efficiency of each process was determined by measuring the absorbance at two visible wavelengths, 466 nm for MO and 498 nm for CR, and the total organic carbon (TOC), i.e. decolorization and mineralization, respectively. In both cases, considerable potential for the degradation of CR and MO was observed - total decolorization of the solution was achieved within 30-60 min, while the TOC removal was in the range 60-90%. CR and MO solutions irradiated without TiO2 nanoparticles showed no observable changes in either decolorization or mineralization. Three different commercially available TiO2 nanoparticles were used: pure-phase anatase, pure-phase rutile, and mixed-phase preparation named Degussa P25. In terms of degradation kinetics, P25 TiO2 exhibited a photocatalytic activity superior to that of pure-phase anatase or rutile. The electric energy consumption per gram of removed TOC was determined. For nearly the same degradation effect, the consumption in the natural solar radiation experiment was more than 60 times lower than in the artificial solar-like radiation experiment. PMID:26160663

  1. Degradation of the herbicide 2, 4-dichlorophenoxyacetic acid (2,4-D) dimethylamine salt by gamma radiation from cobalt-60 in aqueous solution containing humic acid

    NASA Astrophysics Data System (ADS)

    Campos, Sandro X.; Vieira, Eny M.; Cordeiro, Paulo J. M.; Rodrigues-Fo, Edson; Murgu, Michael

    2003-12-01

    In this study, gamma radiation from cobalt-60 was used to degrade the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) dimethylamine salt in water in the presence of humic acid. The 2,4-D dimethylamine salt 1.13×10 -4 mol dm -3 solution was irradiated with different doses. HPLC was used as an analytical technique to determine the degradation rate of herbicide studied. The results showed that the herbicide was completely degraded at an absorbed dose of 3 kGy. Degradation decreased when humic acid was added to all the doses. ESI/MS and MS/MS were used to identify the radiolytic degradation products. A fragmentation path for production of 4.6-dichlororesorcinol, is suggested. The radiolytic yields ( G) were calculated.

  2. A physical model of the photo- and radiation-induced degradation of ytterbium-doped silica optical fibres

    SciTech Connect

    Mady, Franck Duchez, Jean-Bernard Mebrouk, Yasmine Benabdesselam, Mourad

    2014-10-21

    We propose a model to describe the photo- or/and the radiation-induced darkening of ytterbium-doped silica optical fibers. This model accounts for the well-established experimental features of photo-darkening. Degradation behaviors predicted for fibers pumped in harsh environments are also fully confirmed by experimental data reported in the work by Duchez et al. (this proceeding), which gives a detailed characterization of the interplay between the effects of the pump and those of a superimposed ionizing irradiation (actual operation conditions in space-based applications for instance). In particular, dependences of the darkening build-up on the pump power, the total ionizing dose and the dose rate are all correctly reproduced. The presented model is a ‘sufficient’ one, including the minimal physical ingredients required to reproduce experimental features. Refinements could be proposed to improve, e.g., quantitative kinetics.

  3. Thermal degradation analysis of deuterium-ion-implanted V25Cr40Ti35 using synchrotron radiation photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Tode, Mayumi; Harries, James R.; Teraoka, Yuden; Yoshigoe, Akitaka

    The thermal degradation of a native oxide layer on the hydrogen storage alloy V25Cr40Ti35 and the thermal desorption property of deuterium molecules were studied by synchrotron radiation soft X-ray photoelectron spectroscopy and thermal desorption mass spectrometry. Photoelectron spectra of O-1s, C-1s, V-2p, Cr-2p, and Ti-2p were observed for an as-received sample and a deuterium-ion-implanted one. Although the oxide layer changed dramatically by thermal annealing between 373 K and 473 K for the un-implanted sample, the change of the deuterium-ion-implanted sample was lying between 473 K and 573 K corresponding to D2 desorption. The implantation of deuterium resulted in the stabilization of the surface oxide layer by approximately 100 deg.

  4. Radiation synthesis of CdS/reduced graphene oxide nanocomposites for visible-light-driven photocatalytic degradation of organic contaminant

    NASA Astrophysics Data System (ADS)

    Fu, Xiaoyang; Zhang, Youwei; Cao, Pengfei; Ma, Huiling; Liu, Pinggui; He, Lihua; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2016-06-01

    CdS/reduced graphene oxide (CdS/RGO) nanocomposites were successfully synthesized via a one-step gamma-ray radiation-induced reduction method. The composition and structure of the prepared nanocomposites were characterized by thermal gravimetric analysis, micro FTIR spectroscopy, UV-vis spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. It was found that increasing dose could improve the degree of reduction of graphite oxide (GO), and the feed ratio of GO to CdCl2·2.5H2O significantly influenced the size and dispersion of the CdS nanoparticles. The nanocomposites prepared under dose of 300 kGy and the feed ratio of GO to CdCl2·2.5H2O 1.0 wt% exhibited high visible-light photocatalytic performance for the degradation of Rhodamine B with degradation efficiency of 93%. This work provides a novel and facile method to produce the nanocomposites as efficient photocatalysts for the removal of organic contaminants from aqueous solution.

  5. The antioxidant properties of oligo sodium alginates prepared by radiation-induced degradation in aqueous and hydrogen peroxide solutions

    NASA Astrophysics Data System (ADS)

    Şen, Murat; Atik, Hanife

    2012-07-01

    In this study, the radiation-induced degradation of sodium alginates (NaAlg), having different guluronic acids (G) and mannuronic acid (M) ratios, (G/M), in aqueous and hydrogen peroxide solutions were investigated first; after that, the antioxidative properties of the oligo sodium alginates prepared were identified. Radiation degradation yield values, G(S), were determined for each irradiation condition and compared with those of the dry-state-irradiated NaAlg. The results showed that the oligo sodium alginates with M from 1000 to 3750 Da could be easily prepared by γ-irradiation of NaAlg solution in the presence of small amount of hydrogen peroxide at low doses (below 5.0 kGy) and by controlling the G/M. The antioxidant properties of the fractions with various molecular weight and G/M were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPHrad ), and 50% inhibition concentrations of LF120 NaAlg, which was irradiated in aqueous solution and H2O2 solution at a dose of 2.5 kGy and having number average molecular weights of 10.2 and 3.75 kDa were found to be 10.0 and 2.5 mg/ml, respectively. The results demonstrated that its molecular weight was an important factor in controlling the antioxidant properties of NaAlg, and due to the sharp decrease in molecular weight in the case of aqueous media irradiation the effect of G/M of initial polymer became unimportant whereas the dry-state-irradiated NaAlgs behaved conversely.

  6. Management of Pediatric Spinal Cord Astrocytomas: Outcomes With Adjuvant Radiation

    SciTech Connect

    Guss, Zachary D.; Moningi, Shalini; Jallo, George I.; Cohen, Kenneth J.; Wharam, Moody D.; Terezakis, Stephanie A.

    2013-04-01

    Purpose: Pediatric intramedullary spinal cord tumors are exceedingly rare; in the United States, 100 to 200 cases are recognized annually, of these, most are astrocytomas. The purpose of this study is to report the outcomes in pediatric patients with spinal cord astrocytomas treated at a tertiary care center. Methods and Materials: An institutional review board-approved retrospective single-institution study was performed for pediatric patients with spinal cord astrocytomas treated at our hospital from 1990 to 2010. The patients were evaluated on the extent of resection, progression-free survival (PFS), and development of radiation-related toxicities. Kaplan-Meier curves and multivariate regression model methods were used for analysis. Results: Twenty-nine patients were included in the study, 24 with grade 1 or 2 (low-grade) tumors and 5 with grade 3 or 4 (high-grade) tumors. The median follow-up time was 55 months (range, 1-215 months) for patients with low-grade tumors and 17 months (range, 10-52 months) for those with high-grade tumors. Thirteen patients in the cohort received chemotherapy. All patients underwent at least 1 surgical resection. Twelve patients received radiation therapy to a median radiation dose of 47.5 Gy (range, 28.6-54.0 Gy). Fifteen patients with low-grade tumors and 1 patient with a high-grade tumor exhibited stable disease at the last follow-up visit. Acute toxicities of radiation therapy were low grade, whereas long-term sequelae were infrequent and manageable when they arose. All patients with low-grade tumors were alive at the last follow-up visit, compared with 1 patient with a high-grade tumor. Conclusion: Primary pediatric spinal cord astrocytomas vary widely in presentation and clinical course. Histopathologic grade remains a major prognostic factor. Patients with low-grade tumors tend to have excellent disease control and long-term survival compared to those with high-grade tumors. This experience suggests that radiation therapy

  7. Data base management system for a radiation safety program

    SciTech Connect

    McKetty, M.H.; Roach, D.M. )

    1991-03-01

    A data base management system (DBMS) has been developed that simplifies the retrieval of data concerning radioisotope use at a university and hospital. The system customizes software that is commercially available to perform several functions. Reports can be developed concerning receipt of radioactive materials, radioactive waste disposal, and research proposals submitted by investigators. Reports can be prepared that utilize the software's ability to perform numerical calculations. The main advantage of the DBMS is that it allows the easy retrieval of information that is used in the day-to-day operation of a radiation safety office; it also provides easy access and manipulation of data for the preparation of reports, budget proposals, and justifications for purchases.

  8. Determinants of farmers' tree planting investment decision as a degraded landscape management strategy in the central highlands of Ethiopia

    NASA Astrophysics Data System (ADS)

    Gessesse, B.; Bewket, W.; Bräuning, A.

    2015-11-01

    Land degradation due to lack of sustainable land management practices are one of the critical challenges in many developing countries including Ethiopia. This study explores the major determinants of farm level tree planting decision as a land management strategy in a typical framing and degraded landscape of the Modjo watershed, Ethiopia. The main data were generated from household surveys and analysed using descriptive statistics and binary logistic regression model. The model significantly predicted farmers' tree planting decision (Chi-square = 37.29, df = 15, P<0.001). Besides, the computed significant value of the model suggests that all the considered predictor variables jointly influenced the farmers' decision to plant trees as a land management strategy. In this regard, the finding of the study show that local land-users' willingness to adopt tree growing decision is a function of a wide range of biophysical, institutional, socioeconomic and household level factors, however, the likelihood of household size, productive labour force availability, the disparity of schooling age, level of perception of the process of deforestation and the current land tenure system have positively and significantly influence on tree growing investment decisions in the study watershed. Eventually, the processes of land use conversion and land degradation are serious which in turn have had adverse effects on agricultural productivity, local food security and poverty trap nexus. Hence, devising sustainable and integrated land management policy options and implementing them would enhance ecological restoration and livelihood sustainability in the study watershed.

  9. Determinants of farmers' tree-planting investment decisions as a degraded landscape management strategy in the central highlands of Ethiopia

    NASA Astrophysics Data System (ADS)

    Gessesse, Berhan; Bewket, Woldeamlak; Bräuning, Achim

    2016-04-01

    Land degradation due to lack of sustainable land management practices is one of the critical challenges in many developing countries including Ethiopia. This study explored the major determinants of farm-level tree-planting decisions as a land management strategy in a typical farming and degraded landscape of the Modjo watershed, Ethiopia. The main data were generated from household surveys and analysed using descriptive statistics and a binary logistic regression model. The model significantly predicted farmers' tree-planting decisions (χ2 = 37.29, df = 15, P < 0.001). Besides, the computed significant value of the model revealed that all the considered predictor variables jointly influenced the farmers' decisions to plant trees as a land management strategy. The findings of the study demonstrated that the adoption of tree-growing decisions by local land users was a function of a wide range of biophysical, institutional, socioeconomic and household-level factors. In this regard, the likelihood of household size, productive labour force availability, the disparity of schooling age, level of perception of the process of deforestation and the current land tenure system had a critical influence on tree-growing investment decisions in the study watershed. Eventually, the processes of land-use conversion and land degradation were serious, which in turn have had adverse effects on agricultural productivity, local food security and poverty trap nexus. Hence, the study recommended that devising and implementing sustainable land management policy options would enhance ecological restoration and livelihood sustainability in the study watershed.

  10. Polyaryl ethers and related polysiloxane copolymer molecular coatings preparation and radiation degradation. Final report

    SciTech Connect

    Mcgrath, J.E.; Hedrick, J.L.; Webster, D.C.; Johnson, B.C.; Mohanty, D.K.; Yilgor, I.

    1983-06-01

    Poly(arylene ether sulfones) comprise a class of materials known as engineering thermoplastics which have a variety of important applications. These polymers are tough, rigid materials with good mechanical properties over a wide temperature range, and they are processed by conventional methods into products typically having excellent hydrolytic, thermal, oxidative and dimensional stability. Wholly aromatic random copolymers of hydroquinone and biphenol with 4.4 prime dichlorodiphenyl sulfone were synthesized via mechanical nucleophilic displacement. Their structures were characterized and mechanical behavior studied. These tough, ductile copolymers show excellent radiation resistance to electron beam treatment and retain much of the mechanical properties up to at least 700 Mrads under argon.

  11. Radiation-induced catalytic degradation of p-nitrophenol (PNP) in the presence of TiO 2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Shaoqing, Yu; Jun, Hu; Jianlong, Wang

    2010-10-01

    The gamma radiation induced catalytic degradation of p-nitrophenol (PNP) in the presence of titanium dioxide (TiO 2) nanoparticles in aqueous solution was investigated. The initial concentration of PNP solution was 50 mg/L, and the additional TiO 2 doses were 0, 0.5, 1.0, and 2.0 g/L. The experimental results indicated that the PNP decomposition kinetics conformed to the modified pseudo-first order reaction equation under all applied conditions. When the TiO 2 dose was in the range of 0-2.0 g/L, the effect of additional TiO 2 on PNP decomposition rate was not obvious because PNP could be removed quite well by irradiation even in the absence of TiO 2 nanoparticles; however, the removal of total organic carbon (TOC) and total nitrogen (TN) was significantly accelerated in the presence of TiO 2 nanoparticles, the TOC removal efficiency increased from about 16% to 42%, and therefore the mineralization of PNP could be enhanced by TiO 2 nanoparticles. The inorganic nitrogen products were quantitatively measured to estimate the decomposition degree of PNP. The major aromatic intermediates, as well as carboxylic acids were identified by LCMS and IC. Possible reactions involved in radiation induced catalytic decomposition of PNP in aqueous solutions were proposed.

  12. Radiation-induced degradation of butyl rubber vulcanized by three different crosslinking systems

    NASA Astrophysics Data System (ADS)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C. L.; Lugao, Ademar B.

    2012-08-01

    Butyl rubber (IIR) is an isobutylene/isoprene copolymer and is provided with good properties including low permeability to gases, good thermal stability and high resistance to oxygen and ozone action, among others. It is well known that the major effect of ionizing radiations on butyl rubber is chain scission accompanied with a significant reduction in molar mass. This work aimed to study the effects of gamma radiation on the properties of butyl rubbers vulcanized by three different curing systems, such as, the ones based on sulfur, sulfur donor and phenolic resin to identify which curing system is the most stable under irradiation. The butyl rubber vulcanized by three different systems was gamma irradiated with doses of 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 kGy. Irradiated and non-irradiated samples were characterized by the following techniques: tensile, elongation and hardness. It was observed that doses higher than 150 kGy practically destroy the assessed properties for all butyl compounds, irrespective of the vulcanization system used; however compounds cured with phenolic resin showed a decrease in properties proportional to the dose.

  13. Biological effect of radiation-degraded alginate on flower plants in tissue culture.

    PubMed

    Le, Q Luan; Nguyen, Q Hien; Nagasawa, Naotsugu; Kume, Tamikazu; Yoshii, Fumio; Nakanishi, Tomoko M

    2003-12-01

    Alginate with a weight-average molecular mass (Mw) of approx. 9.04 x 10(5) Da was irradiated at 10-200 kGy in 4% (w/v) aqueous solution. The degraded alginate product was used to study its effectiveness as a growth promoter for plants in tissue culture. Alginate irradiated at 75 kGy with an Mw of approx. 1.43 x 10(4) Da had the highest positive effect in the growth of flower plants, namely limonium, lisianthus and chrysanthemum. Treatment of plants with irradiated alginate at concentrations of 30-200 mg/l increased the shoot multiplication rate from 17.5 to 40.5% compared with control. In plantlet culture, 100 mg/l irradiated alginate supplementation enhanced shoot height (9.7-23.2%), root length (9.7-39.4%) and fresh biomass (8.1-19.4%) of chrysanthemum, lisianthus and limonium compared with that of the untreated control. The survival ratios of the transferred flower plantlets treated with irradiated alginate were almost the same as the control value under greenhouse conditions. However, better growth was attained for the treated plantlets. PMID:12901723

  14. Radiation Induced Degradation of the White Thermal Control Paints Z-93 and Z-93P

    NASA Technical Reports Server (NTRS)

    Edwards, D. L.; Zwiener, J. M.; Wertz, G. E.; Vaughn, J. A.; Kamenetzky, R. R.; Finckenor, M. M.; Meshishnek, M. J.

    1996-01-01

    This paper details a comparison analysis of the zinc oxide pigmented white thermal control paints Z-93 and Z-93P. Both paints were simultaneously exposed to combined space environmental effects and analyzed using an in-vacuo reflectance technique. The dose applied to the paints was approximately equivalent to 5 years in a geosynchronous orbit. This comparison analysis showed that Z-93P is an acceptable substitute for Z-93. Irradiated samples of Z-93 and Z-93P were subjected to additional exposures of ultraviolet (UV) radiation and analyzed using the in-vacuo reflectance technique to investigate UV activated reflectance recovery. Both samples showed minimal UV activated reflectance recovery after an additional 190 equivalent sun hour (ESH) exposure. Reflectance response utilizing nitrogen as a repressurizing gas instead of air was also investigated. This investigation found the rates of reflectance recovery when repressurized with nitrogen are slower than when repressurized with air.

  15. Quantifiler® Trio Kit and forensic samples management: a matter of degradation.

    PubMed

    Vernarecci, Stefano; Ottaviani, Enrica; Agostino, Alessandro; Mei, Elisabetta; Calandro, Lisa; Montagna, Paola

    2015-05-01

    DNA collected from crime scenes may have experienced different levels of degradation. This is mainly due to sample exposure to different environmental factors. The impact of DNA degradation on short tandem repeat (STR) profiling can lead to partial or null information and in some cases, the identification of the trace may fail. The availability of a system enabling the assessment not only of the quantity of the DNA but also of its quality in terms of degradation would result in shorter time for sample processing, more reliable identifications and cost reduction by predicting the quality of the DNA profiles prior to STR analysis. We report here a study on 181 selected degraded DNA samples extracted from real crime scene evidence. The selected samples were processed by combining the use of a new commercial quantification kit (Quantifiler® Trio) with a new 24 marker multiplex PCR amplification kit (Globalfiler® Kit). Applying different statistical analyses we investigated the reliability of the Degradation Index provided by the Quantifiler® Trio in determining the level of DNA degradation in a forensic sample. This useful information can be used to predict the quality of the profile obtained after STR amplification. The combination of such a quantification kit with different PCR protocols allowed us to define practical guidelines for processing degraded forensic DNA samples with a simplified and comprehensive approach. PMID:25544252

  16. The NIOSH Radiation Dose Reconstruction Project: managing technical challenges.

    PubMed

    Moeller, Matthew P; Townsend, Ronald D; Dooley, David A

    2008-07-01

    Approximately two years after promulgation of the Energy Employees Occupational Illness Compensation Program Act, the National Institute for Occupational Safety and Health Office of Compensation and Analysis Support selected a contractor team to perform many aspects of the radiation dose reconstruction process. The project scope and schedule necessitated the development of an organization involving a comparatively large number of health physicists. From the initial stages, there were many technical and managerial challenges that required continuous planning, integration, and conflict resolution. This paper identifies those challenges and describes the resolutions and lessons learned. These insights are hopefully useful to managers of similar scientific projects, especially those requiring significant data, technical methods, and calculations. The most complex challenge has been to complete defensible, individualized dose reconstructions that support timely compensation decisions at an acceptable production level. Adherence to applying claimant-favorable and transparent science consistent with the requirements of the Act has been the key to establishing credibility, which is essential to this large and complex project involving tens of thousands of individual stakeholders. The initial challenges included garnering sufficient and capable scientific staff, developing an effective infrastructure, establishing necessary methods and procedures, and integrating activities to ensure consistent, quality products. The continuing challenges include maintaining the project focus on recommending a compensation determination (rather than generating an accurate dose reconstruction), managing the associated very large data and information management challenges, and ensuring quality control and assurance in the presence of an evolving infrastructure. The lessons learned concern project credibility, claimant favorability, project priorities, quality and consistency, and critical

  17. First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application

    SciTech Connect

    Lordi, V; Aberg, D; Erhart, P; Wu, K J

    2007-07-30

    The development of high resolution, room temperature semiconductor radiation detectors requires the introduction of materials with increased carrier mobility-lifetime ({mu}{tau}) product, while having a band gap in the 1.4-2.2 eV range. AlSb is a promising material for this application. However, systematic improvements in the material quality are necessary to achieve an adequate {mu}{tau} product. We are using a combination of simulation and experiment to develop a fundamental understanding of the factors which affect detector material quality. First principles calculations are used to study the microscopic mechanisms of mobility degradation from point defects and to calculate the intrinsic limit of mobility from phonon scattering. We use density functional theory (DFT) to calculate the formation energies of native and impurity point defects, to determine their equilibrium concentrations as a function of temperature and charge state. Perturbation theory via the Born approximation is coupled with Boltzmann transport theory to calculate the contribution toward mobility degradation of each type of point defect, using DFT-computed carrier scattering rates. A comparison is made to measured carrier concentrations and mobilities from AlSb crystals grown in our lab. We find our predictions in good quantitative agreement with experiment, allowing optimized annealing conditions to be deduced. A major result is the determination of oxygen impurity as a severe mobility killer, despite the ability of oxygen to compensation dope AlSb and reduce the net carrier concentration. In this case, increased resistivity is not a good indicator of improved material performance, due to the concomitant sharp reduction in {mu}{tau}.

  18. Radiolysis of N-acetyl amino acids as model compounds for radiation degradation of polypeptides

    NASA Astrophysics Data System (ADS)

    Wayne Garrett, R.; Hill, David J. T.; Ho, Sook-Ying; O'Donnell, James H.; O'Sullivan, Paul W.; Pomery, Peter J.

    Radiation chemical yields of (i) the volatile radiolysis products and (ii) the trapped free radicals from the y-radiolysis of the N-acetyl derivatives of glycine, L-valine, L-phenylalanine and L-tyrosine in the polycrystalline state have been determined at room temperature (303 K). Carbon dioxide was found to be the major molecular product for all these compounds with G(CO 2) varying from 0.36 for N-acetyl-L-tyrosine to 8 for N-acetyl-L-valine. There was evidence for some scission of the N-C α bond, indicated by the production of acetamide and the corresponding aliphatic acid, but the determination reaction was found to be of much lesser importance than the decarboxylation reaction. A protective effect of the aromatic ring in N-acetyl-L-phenylalanine and in N-acetyl-L-tyrosine was indicated by the lower yields of volatile products for these compounds. The yields of trapped free radicals were found to vary with the nature of the amino acid side chain, increasing with chain length and chain branching. The radical yields were decreased by incorporation of an aromatic moiety in the side chain, this effect being greater for the tyrosyl side chain than for the phenyl side chain. The G(R·) values showed a good correlation with G(CO 2) indicating that a common reaction may be involved in radical production and carbon dioxide formation.

  19. Enhancing the biological degradability of sulfamethoxazole by ionizing radiation treatment in aqueous solution

    NASA Astrophysics Data System (ADS)

    Sági, Gyuri; Kovács, Krisztina; Bezsenyi, Anikó; Csay, Tamás; Takács, Erzsébet; Wojnárovits, László

    2016-07-01

    Changes of biodegradability and toxicity were followed up on aqueous solutions of sulfamethoxazole (SMX), during ionizing radiation treatment. The biodegradability of SMX (0.1 mmol dm-3) was specified by five-day biological oxygen demand (BOD5), using municipal activated sludge, and the results showed an improvement with applying only 0.4 kGy dose. BOD5 further increased with prolonged irradiation, indicating a conversion of SMX, a non-biodegradable compound, to biologically treatable substances. At 2.5 kGy dose, the BOD5/COD ratio increased from 0 to 0.16. The total organic carbon (TOC) content showed a decrease of only 15% at this point, thus high degree of mineralization is not necessary to make SMX digestible for the low concentrations of microorganisms used during BOD5 measurements. Increment in respiration inhibition of municipal activated sludge was observed with increasing the dose. The EC50 values showed a decrease of one order of magnitude when changing the dose from 0.4 kGy to 2.5 kGy. The increase of inhibition and formation of H2O2 showed a strong correlation.

  20. Management and Analysis of Radiation Portal Monitor Data

    SciTech Connect

    Rowe, Nathan C; Alcala, Scott; Crye, Jason Michael; Lousteau, Angela L

    2014-01-01

    Oak Ridge National Laboratory (ORNL) receives, archives, and analyzes data from radiation portal monitors (RPMs). Over time the amount of data submitted for analysis has grown significantly, and in fiscal year 2013, ORNL received 545 gigabytes of data representing more than 230,000 RPM operating days. This data comes from more than 900 RPMs. ORNL extracts this data into a relational database, which is accessed through a custom software solution called the Desktop Analysis and Reporting Tool (DART). DART is used by data analysts to complete a monthly lane-by-lane review of RPM status. Recently ORNL has begun to extend its data analysis based on program-wide data processing in addition to the lane-by-lane review. Program-wide data processing includes the use of classification algorithms designed to identify RPMs with specific known issues and clustering algorithms intended to identify as-yet-unknown issues or new methods and measures for use in future classification algorithms. This paper provides an overview of the architecture used in the management of this data, performance aspects of the system, and additional requirements and methods used in moving toward an increased program-wide analysis paradigm.

  1. Channelling science into policy: enabling best practices from research on land degradation and sustainable land management in dryland Africa.

    PubMed

    Stringer, Lindsay C; Dougill, Andrew J

    2013-01-15

    Demands are increasing for scientific research to be explicitly and demonstrably policy relevant. Research funders are requiring greater returns on their investments and scientists are expected to demonstrate clearly how their research can inform policy and regulation to deliver positive consequences for societal, economic and environmental wellbeing. Within the co-evolving context of environmental management research in dryland Africa and the policy approaches designed to mitigate land degradation, few academic analyses have deconstructed the practical 'bottom-up' actions that can help to channel scientific research into national decision-making and policy. Similarly, while international platforms developed by the United Nations Convention to Combat Desertification have started to facilitate greater knowledge exchange between scientists and policymakers, analyses have failed to consider the powerful informal actions that scientists can take to allow their research to inform evidence-based international policy. Drawing on examples in the literature from research on land degradation and sustainable land management across sub-Saharan African drylands, we identify key enabling activities that help make scientific research more visible, accessible to, and compatible with, policy processes at local, national and international levels. We argue that these enablers are applicable to other environmental research areas beyond land degradation, and suggest that improved understanding of science into policy processes that look across multiple scales and levels will help researchers and policy-makers to better match information supply and demand to the mutual benefit of both groups. PMID:23158525

  2. USING TECHNOLOGY TO SUPPORT PROACTIVE MANAGEMENT OF MATERIALS DEGRADATION FOR THE U.S. NUCLEAR REGULATORY COMMISSION

    SciTech Connect

    Taylor, W Boyd; Knobbs, Katherine J.; Carpenter, C. E.; Malik, Shah

    2010-07-19

    The majority of the U.S. reactor fleet is applying for license renewal to extend the operating life from the current 40 years to 60 years, and there is now active interest in extending the operating life to beyond 60 years. Many plants are also applying for increases in power rating and both of these changes increases the need for an improved understanding of materials degradation. Many materials degrade over time and much is known about the degradation of materials under normal environmental conditions; however, less is known about the characteristics of materials degradation when the environment is subject to higher than normal radiological conditions over extended periods of time. Significant efforts are being made by industrial, academic and regulatory groups worldwide to identify, classify and mitigate potential problems arising from degradation of components in this context. From a regulatory perspective, the U.S. Nuclear Regulatory Commission (USNRC) is very interested in being able to identify ways to insure their licensees proactively manage the identification of materials degradation and the mitigation of its effects. To date, the USNRC has consolidated “generic” programs for mitigating aging issues in the two volume Generic Aging Lessons Learned (GALL) Report (NUREG-1801) [1][2], and have encouraged applicants for license renewal to use these programs where applicable in their plant when applying for renew of their reactor’s license. The USNRC has also published a comprehensive report entitled Expert Panel Report on Proactive Materials Degradation (NUREG/CR-6923) [3] that inventories the types of degradation mechanisms that could exist in each component of a Light Water Reactor (LWR) and each degradation mechanism is assessed regarding how much is known about mitigating its effects. Since the number of plant designs and materials used varies greatly within the U.S. fleet, there are many variations to implementing aging management programs (AMPs

  3. Degradation and resilience of soils

    PubMed Central

    Lal, R.

    1997-01-01

    Debate on global soil degradation, its extent and agronomic impact, can only be resolved through understanding of the processes and factors leading to establishment of the cause-effect relationships for major soils, ecoregions, and land uses. Systematic evaluation through long-term experimentation is needed for establishing quantitative criteria of (i) soil quality in relation to specific functions; (ii) soil degradation in relation to critical limits of key soil properties and processes; and (iii) soil resilience in relation to the ease of restoration through judicious management and discriminate use of essential input. Quantitative assessment of soil degradation can be obtained by evaluating its impact on productivity for different land uses and management systems. Interdisciplinary research is needed to quantify soil degradation effects on decrease in productivity, reduction in biomass, and decline in environment quality throught pollution and eutrophication of natural waters and emission of radiatively-active gases from terrestrial ecosystems to the atmosphere. Data from long-term field experiments in principal ecoregions are specifically needed to (i) establish relationships between soil quality versus soil degradation and soil quality versus soil resilience; (ii) identify indicators of soil quality and soil resilience; and (iii) establish critical limits of important properties for soil degradation and soil resilience. There is a need to develop and standardize techniques for measuring soil resilience.

  4. Implications for accident management of adding water to a degrading reactor core

    SciTech Connect

    Kuan, P.; Hanson, D.J.; Pafford, D.J.; Quick, K.S.; Witt, R.J.

    1994-02-01

    This report evaluates both the positive and negative consequences of adding water to a degraded reactor core during a severe accident. The evaluation discusses the earliest possible stage at which an accident can be terminated and how plant personnel can best respond to undesired results. Specifically discussed are (a) the potential for plant personnel to add water for a range of severe accidents, (b) the time available for plant personnel to act, (c) possible plant responses to water added during the various stages of core degradation, (d) plant instrumentation available to understand the core condition and (e) the expected response of the instrumentation during the various stages of severe accidents.

  5. Management of radiation dermatitis in a patient after mastectomy.

    PubMed

    McDougall, Carol J; Franklin, Lynette E; Gresle, Suzanne O

    2005-01-01

    Women who are diagnosed with breast cancer and undergoing chemotherapy and radiation are at high risk of developing acute radiation dermatitis. The purpose of this case study is to explore an alternative topical therapy for skin toxicity in the post-radiation care of a patient with a history of breast cancer. The patient, a 54-year-old white female, was treated by modified radical mastectomy, chemotherapy, and radiation. During post-radiation therapy the patient developed wet desquamation reaction over the midincision line into the right axilla. Balsam Peru, hydrogenated castor oil, trypsin (Xenaderm Healthpoint, San Antonio, Tex) was trialed to evaluate efficacy in providing wound healing to the denuded skin. Within 14 days of treatment, the area was completely healed and topical therapy stopped. This case study provides the basis for further research into the area of topical therapy for women with moist desquamation after radiation for breast cancer. PMID:16234729

  6. KERMA-based radiation dose management system for real-time patient dose measurement

    NASA Astrophysics Data System (ADS)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  7. Site/Systems Operations, Maintenance and Facilities Management of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site

    SciTech Connect

    Wu, Susan

    2005-08-01

    This contract covered the site/systems operations, maintenance, and facilities management of the DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site.

  8. Base-level management of radio-frequency radiation-protection program. Final report

    SciTech Connect

    Rademacher, S.E.; Montgomery, N.D.

    1989-04-01

    AFOEHL developed this report to assist the base-level aerospace medical team manage their radio-frequency radiation-protection program. This report supersedes USAFOEHL Report 80-42, 'A Practical R-F Guide for BEES.'

  9. Base-level management of radio-frequency radiation-protection program. Final report

    SciTech Connect

    Rademacher, S.E.; Montgomery, N.D.

    1989-04-01

    AFOEHL developed this report to assist the base-level aerospace medical team manage their radio-frequency radiation protection program. This report supersedes USAFOEHL Report 80-42, 'A practical R-F Guide for BEES.'

  10. Experiences and Management of Pregnant Radiation Workers at the Pacific Northwest National Laboratory

    SciTech Connect

    Bliss, Mary; Bowyer, Sonya M.; Bryant, Janet L.; Lipton, Mary S.; Wahl, Karen L.

    2001-03-06

    Radiation workers at the Pacific Northwest National Laboratory are divided into two classes based on whether or not they can encounter radioactive contamination in the normal course of their work. Level I workers primarily handle sealed radioactive materials such as those used to calibrate detectors. Level II workers perform benchtop chemistry. The U.S. Department of Energy has strict guidelines on the management of pregnant radiation workers. Staff members may voluntarily notify their line managers of a pregnancy and be subjected to stringent radiation exposure limits for the developing fetus. The staff member and manager develop a plan to limit and monitor radiation dose for the remainder of the pregnancy. Several examples of dose management plans and case examples of the impact of pregnancy on staff member?s technical work and projects will be presented.

  11. Management of Radiation Injuries by Panax ginseng Extract

    PubMed Central

    Verma, Preeti; Jahan, Swafiya; Kim, Tae Hawn; Goyal, Pradeep Kumar

    2011-01-01

    Chemical radiation protection is an important strategy to protect living beings against the deleterious effects of radiation. In the present study, the radioprotective effect of hydro-alcoholic extract of Panax ginseng extract (PGR-HAE) was studied on radiation-induced deleterious alterations in Swiss albino mice. Oral administration of such extract (25 mg/kg b wt/day/animal) for 5 consecutive days, half an h. before whole-body exposure to 6 Gy gamma radiation, enhanced the 30 days survival and also inhibited the radiogenic sickness, weight loss and life shortening. PGR-HAE ameliorated radiation induced depletion in blood constituents at different necropsy intervals between 12 h to 30 d, and significantly increased the number of femoral spleen colony forming units that survived after irradiation. Furthermore, it checked depletion of glutathione and antioxidant enzymes (superoxide dismutase, catalase, and glutathione S-transferase) as well as elevation of lipid peroxidation (LPO) level in blood and liver. The significant reduction in the yield of LPO demonstrates that PGR-HAE protects the membranes against radiation-induced oxidative damage. These findings conclude that such plant extract provides significant radioprotection, and it may be potentially valuable in the prevention of injuries caused during planned and unplanned radiation exposure. PMID:23717069

  12. Immediate breast reconstruction-impact on radiation management.

    PubMed Central

    Shankar, Ravi A.; Nibhanupudy, J. Rao; Sridhar, Rajagopalan; Ashton, Cori; Goldson, Alfred L.

    2003-01-01

    Breast reconstruction is an option for women undergoing modified radical mastectomy due to a diagnosis of breast cancer. In certain patients, breast reconstruction is performed by insertion of a temporary tissue expander prior to the placement of permanent breast implants. Some of these patients, following mastectomy, may require chest wall irradiation to prevent loco regional relapse. The compatibility of radiation and tissue expanders placed in the chest wall is of major concern to the radiation oncologist. Clinically undetectable changes can occur in the tissue expander during the course of radiation therapy. This can lead to radiation treatment set-up changes, variation in tissue expansion resulting in unwanted cosmesis, and deviation from the prescribed radiation dose leading to over and/or under dosing of tumor burden. At Howard University hospital, a CT scan was utilized to evaluate the status of the temporary tissue expander during radiation treatment to enable us to prevent radiation treatment related complications resulting from dosimetric discrepancies. CT images of the tissue expander were obtained through the course of treatment. To avoid a 'geographic miss' the amount of fluid injected into the tissue expander was kept constant following patient's satisfaction with the size of the breast mound. The CT scans allowed better visualization of the prosthesis and its relation to the surrounding tumor bed. This technique ensured that anatomical changes occurring during radiation treatment, if any, were minimized. Repeated dosimetry evaluations showed no changes to the prescribed dose distribution. A CT of the reconstructed breast provides an important quality control. Further studies with greater number of patients are required for confirming this impact on radiation treatment. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:12749619

  13. Advances in radiation oncology for the management of oropharyngeal tumors.

    PubMed

    Gunn, G Brandon; Frank, Steven J

    2013-08-01

    The major benefits of modern radiation therapy (eg, intensity-modulated [x-ray] radiation therapy [IMRT]) for oropharyngeal cancer are reduced xerostomia and better quality of life. Intensity-modulated proton therapy may provide additional advantages over IMRT by reducing radiation beam-path toxicities. Several acute and late treatment-related toxicities and symptom constellations must be kept in mind when designing and comparing future treatment strategies, particularly because currently most patients with oropharyngeal carcinoma present with human papillomavirus-positive disease and are expected to have a high probability of long-term survival after treatment. PMID:23910474

  14. The Role for Radiation Therapy in the Management of Sarcoma.

    PubMed

    Leachman, Brooke K; Galloway, Thomas J

    2016-10-01

    Although there is no consensus regarding the optimal sequencing of external beam radiotherapy and surgery for extremity soft tissue sarcoma, radiation therapy delivered before or after limb-sparing surgery significantly improves local control, particularly for high-grade tumors. Large database analyses suggest that improved local control may translate into an overall survival benefit. Best practices require ample communication between the radiation and surgical teams to ensure appropriate tissues are targeted, unnecessary radiation is avoided, and patients are afforded the best opportunity for cure while maintaining function. Modern experiences with intensity-modulated radiotherapy/image-guided radiation therapy suggest toxicity is reduced through field size reduction and precise targeting, improving the therapeutic ratio. PMID:27542646

  15. Impact of heat and water management on proton exchange membrane fuel cells degradation in automotive application

    NASA Astrophysics Data System (ADS)

    Nandjou, F.; Poirot-Crouvezier, J.-P.; Chandesris, M.; Blachot, J.-F.; Bonnaud, C.; Bultel, Y.

    2016-09-01

    In Proton Exchange Membrane Fuel Cells, local temperature is a driving force for many degradation mechanisms such as hygrothermal deformation and creep of the membrane, platinum dissolution and bipolar plates corrosion. In order to investigate and quantify those effects in automotive application, durability testing is conducted in this work. During the ageing tests, the local performance and temperature are investigated using in situ measurements of a printed circuit board. At the end of life, post-mortem analyses of the aged components are conducted. The experimental results are compared with the simulated temperature and humidity in the cell obtained from a pseudo-3D multiphysics model in order to correlate the observed degradations to the local conditions inside the stack. The primary cause of failure in automotive cycling is pinhole/crack formation in the membrane, induced by high variations of its water content over time. It is also observed that water condensation largely increases the probability of the bipolar plates corrosion while evaporation phenomena induce local deposits in the cell.

  16. Main principles of radiation protection and their applications in waste management

    SciTech Connect

    Devgun, J.S.

    1993-09-01

    The average exposure for an individual from such background in the United States is about 300 mrem per year with approximately 200 mrem of this coming from radon exposure alone. In addition to the natural sources of background radiation, a very small amount of the background radiation occurs due to the nuclear weapons test fallout. Manmade sources of radiation also include certain consumer products, industrial and research use of radioisotopes, medical X-rays, and radiopharmaceuticals. When all sources, natural and man-made, are taken into account, the National Council on Radiation Protection and Measurements (NCRP) has estimated that the average annual dose to individuals in the US population is 360 mrem (NCRP Report No. 93). In this report the fundamental principles of radiation protection are reviewed, as well as the relevant laws and regulations in the United States and discuss application of radiation protection in radioactive waste management.

  17. Effects of forest management practices in temperate beech forests on bacterial and fungal communities involved in leaf litter degradation.

    PubMed

    Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Jariyavidyanont, Katalee; Kaunzner, Jennifer; Juncheed, Kantida; Uengwetwanit, Tanaporn; Rudloff, Renate; Schulz, Elke; Hofrichter, Martin; Schloter, Michael; Krüger, Dirk; Buscot, François

    2015-05-01

    Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions. PMID:25749938

  18. Ecosystem services from a degraded peatland of Central Kalimantan: implications for policy, planning, and management.

    PubMed

    Law, Elizabeth A; Bryan, Bretr A; Meijaard, Erik; Mallawaarachchi, Thilak; Struebig, Matthew; Wilson, Kerrie A

    2015-01-01

    Increasingly, landscapes are managed for multiple objectives to balance social, economic, and environmental goals. The Ex-Mega Rice Project (EMRP) peatland in Central Kalimantan, Indonesia provides a timely example with globally significant development, carbon, and biodiversity concerns. To inform future policy, planning, and management in the EMRP, we quantified and mapped ecosystem service values, assessed their spatial interactions, and evaluated the potential provision of ecosystem services under future land-use scenarios. We focus on key policy-relevant regulating (carbon stocks and the potential for emissions reduction), provisioning (timber, crops from smallholder agriculture, palm oil), and supporting (biodiversity) services. We found that implementation of existing land-use plans has the potential to improve total ecosystem service provision. We identify a number of significant inefficiencies, trade-offs, and unintended outcomes that may arise. For example, the potential development of existing palm oil concessions over one-third of the region may shift smallholder agriculture into low-productivity regions and substantially impact carbon and biodiversity outcomes. While improved management of conservation zones may enhance the protection of carbon stocks, not all biodiversity features will be represented, and there will be a reduction in timber harvesting and agricultural production. This study highlights how ecosystem service analyses can be structured to better inform policy, planning, and management in globally significant but data-poor regions. PMID:26255358

  19. Prophylaxis and management of acute radiation-induced skin reactions: a systematic review of the literature

    PubMed Central

    Salvo, N.; Barnes, E.; van Draanen, J.; Stacey, E.; Mitera, G.; Breen, D.; Giotis, A.; Czarnota, G.; Pang, J.; De Angelis, C.

    2010-01-01

    Radiation therapy is a common treatment for cancer patients. One of the most common side effects of radiation is acute skin reaction (radiation dermatitis) that ranges from a mild rash to severe ulceration. Approximately 85% of patients treated with radiation therapy will experience a moderate-to-severe skin reaction. Acute radiation-induced skin reactions often lead to itching and pain, delays in treatment, and diminished aesthetic appearance—and subsequently to a decrease in quality of life. Surveys have demonstrated that a wide variety of topical, oral, and intravenous agents are used to prevent or to treat radiation-induced skin reactions. We conducted a literature review to identify trials that investigated products for the prophylaxis and management of acute radiation dermatitis. Thirty-nine studies met the pre-defined criteria, with thirty-three being categorized as prophylactic trials and six as management trials. For objective evaluation of skin reactions, the Radiation Therapy Oncology Group criteria and the U.S. National Cancer Institute Common Toxicity Criteria were the most commonly used tools (65% of the studies). Topical corticosteroid agents were found to significantly reduce the severity of skin reactions; however, the trials of corticosteroids evaluated various agents, and no clear indication about a preferred corticosteroid has emerged. Amifostine and oral enzymes were somewhat effective in preventing radiation-induced skin reactions in phase ii and phase iii trials respectively; further large randomized controlled trials should be undertaken to better investigate those products. Biafine cream (Ortho–McNeil Pharmaceuticals, Titusville, NJ, U.S.A.) was found not to be superior to standard regimes in the prevention of radiation-induced skin reactions (n = 6). In conclusion, the evidence is insufficient to support the use of a particular agent for the prevention and management of acute radiation-induced skin reactions. Future trials should focus

  20. Prophylaxis and management of acute radiation-induced skin reactions: a systematic review of the literature.

    PubMed

    Salvo, N; Barnes, E; van Draanen, J; Stacey, E; Mitera, G; Breen, D; Giotis, A; Czarnota, G; Pang, J; De Angelis, C

    2010-08-01

    Radiation therapy is a common treatment for cancer patients. One of the most common side effects of radiation is acute skin reaction (radiation dermatitis) that ranges from a mild rash to severe ulceration. Approximately 85% of patients treated with radiation therapy will experience a moderate-to-severe skin reaction. Acute radiation-induced skin reactions often lead to itching and pain, delays in treatment, and diminished aesthetic appearance-and subsequently to a decrease in quality of life. Surveys have demonstrated that a wide variety of topical, oral, and intravenous agents are used to prevent or to treat radiation-induced skin reactions. We conducted a literature review to identify trials that investigated products for the prophylaxis and management of acute radiation dermatitis. Thirty-nine studies met the pre-defined criteria, with thirty-three being categorized as prophylactic trials and six as management trials.For objective evaluation of skin reactions, the Radiation Therapy Oncology Group criteria and the U.S. National Cancer Institute Common Toxicity Criteria were the most commonly used tools (65% of the studies). Topical corticosteroid agents were found to significantly reduce the severity of skin reactions; however, the trials of corticosteroids evaluated various agents, and no clear indication about a preferred corticosteroid has emerged. Amifostine and oral enzymes were somewhat effective in preventing radiation-induced skin reactions in phase II and phase III trials respectively; further large randomized controlled trials should be undertaken to better investigate those products. Biafine cream (Ortho-McNeil Pharmaceuticals, Titusville, NJ, U.S.A.) was found not to be superior to standard regimes in the prevention of radiation-induced skin reactions (n = 6).In conclusion, the evidence is insufficient to support the use of a particular agent for the prevention and management of acute radiation-induced skin reactions. Future trials should focus on

  1. Analysis of the degradation of biodegradable mulches in a pepper crop under organic management

    NASA Astrophysics Data System (ADS)

    Moreno, Carmen; González, Sara; Villena, Jaime; Meco, Ramón; María Moreno, Marta

    2016-04-01

    The use of biodegradable mulch materials (biopolymers and papers) as an alternative to polyethylene is increasing nowadays, particularly in organic farming, due to environmental factors. It is necessary to test their functionality under field conditions by identifying, for example, the undesirable early degradation which commonly takes place in some of these biodegradable materials. In this sense, it is quite common and easy to apply the use of visual scales to estimate the level of deterioration of mulches, which can be subjective. Therefore, the objectives of this work are: i) To study the degradation of different mulch materials under field conditions by measuring the soil surface they covered. ii) To compare these soil surface values with the overall assessment of their functionality obtained by visual scales. The trial was performed in an organically grown pepper crop in Ciudad Real (Central Spain) in the 2014 spring-summer season. The mulch materials used were: 1) black polyethylene (15 μm); black biopolymers (15 μm): 2) Mater-Bi® (corn starch based), 3) Sphere 4® (potato starch based), 4) Sphere 6® (potato starch based), 5) Bioflex® (polylactic acid based), 6) Ecovio® (polylactic acid based), 7) Mimgreen® (black paper, 85 g/m2). A randomized complete block design with four replications was adopted. The crop was drip irrigated following the water demand of each treatment. To assess the evolution of the soil surface covered by the mulches, a total of 560 photographs of the superficial (exposed) part and 196 photographs of the buried part of the materials (1415x2831 pixels, 28 pixels/cm) were analyzed by using Adobe Photoshop CS at 15, 30, 45, 60, 90,120, 145 days after transplanting. Additionally, four experts evaluated the functionality of these materials based on the photographs according to a scale from 1 (completely deteriorated material) to 9 (intact material). The results show: i) The superficial part corresponding to the polyethylene and the

  2. Radiation accidents and their management: emphasis on the role of nuclear medicine professionals

    PubMed Central

    Novruzov, Fuad; Vinjamuri, Sobhan

    2014-01-01

    Large-scale radiation accidents are few in number, but those that have occurred have subsequently led to strict regulation in most countries. Here, different accident scenarios involving exposure to radiation have been reviewed. A triage of injured persons has been summarized and guidance on management has been provided in accordance with the early symptoms. Types of casualty to be expected in atomic blasts have been discussed. Management at the scene of an accident has been described, with explanation of the role of the radiation protection officer, the nature of contaminants, and monitoring for surface contamination. Methods for early diagnosis of radiation injuries have been then described. The need for individualization of treatment according to the nature and grade of the combined injuries has been emphasized, and different approaches to the treatment of internal contamination have been presented. The role of nuclear medicine professionals, including physicians and physicists, has been reviewed. It has been concluded that the management of radiation accidents is a very challenging process and that nuclear medicine physicians have to be well organized in order to deliver suitable management in any type of radiation accident. PMID:25004166

  3. A management system integrating radiation protection and safety supporting safety culture in the hospital.

    PubMed

    Almén, A; Lundh, C

    2015-04-01

    Quality assurance has been identified as an important part of radiation protection and safety for a considerable time period. A rational expansion and improvement of quality assurance is to integrate radiation protection and safety in a management system. The aim of this study was to explore factors influencing the implementing strategy when introducing a management system including radiation protection and safety in hospitals and to outline benefits of such a system. The main experience from developing a management system is that it is possible to create a vast number of common policies and routines for the whole hospital, resulting in a cost-efficient system. One of the key benefits is the involvement of management at all levels, including the hospital director. Furthermore, a transparent system will involve staff throughout the organisation as well. A management system supports a common view on what should be done, who should do it and how the activities are reviewed. An integrated management system for radiation protection and safety includes key elements supporting a safety culture. PMID:25429027

  4. A Narrative Review on the Pathophysiology and Management for Radiation Cystitis

    PubMed Central

    Browne, C.; Davis, N. F.; Mac Craith, E.; Lennon, G. M.; Mulvin, D. W.; Quinlan, D. M.; Mc Vey, Gerard P.; Galvin, D. J.

    2015-01-01

    Radiation cystitis is a recognised complication of pelvic radiotherapy. Incidence of radiation cystitis ranges from 23 to 80% and the incidence of severe haematuria ranges from 5 to 8%. High quality data on management strategies for radiation cystitis is sparse. Treatment modalities are subclassified into systemic therapies, intravesical therapies, and hyperbaric oxygen and interventional procedures. Short-term cure rates range from 76 to 95% for hyperbaric oxygen therapy and interventional procedures. Adverse effects of these treatment strategies are acceptable. Ultimately, most patients require multimodal treatment for curative purposes. Large randomised trials exploring emergent management strategies are required in order to strengthen evidence-based treatment strategies. Urologists encounter radiation cystitis commonly and should be familiar with diagnostic modalities and treatment strategies. PMID:26798335

  5. Using conservation value to assess land restoration and management alternatives across a degraded oak savanna landscape

    USGS Publications Warehouse

    Grundel, R.; Pavlovic, N.B.

    2008-01-01

    1. Managers considering restoration of landscapes often face a fundamental challenge - what should be the habitat composition of the restored landscape? We present a method for evaluating an important conservation trade-off inherent in making that decision. 2. Oak savannas and grasslands were historically widespread across central North America but are now rare. Today, in north-west Indiana, USA, habitats spanning a range of woody vegetation density, from nearly treeless open habitats to forests, occur across the conserved landscape where savannas probably once dominated. To understand the benefits of different potential landscape compositions, we evaluated how different proportions of five habitats - open, savanna, woodland, scrub and forest - might affect the conservation value of the north-west Indiana landscape for birds. Two variables of potential conservation importance were examined: species diversity, a measure of avian community richness, and conservation index, the percentage of a bird species' global population occurring on a hectare of landscape, summed across all bird species present. Higher values of conservation index were associated with higher local densities of globally more rare and more threatened species. 3. Conservation index and species diversity were correlated negatively across hypothetical landscapes composed of different proportions of the five habitats. Therefore, a management trade-off existed between conservation index and species diversity because landscapes that maximized species diversity differed from landscapes that maximized conservation index. 4. A landscape of 50% open, 22% savanna, 15% scrub and 13% forest was predicted to represent a compromise at which conservation index and species diversity reached the same percentage of their maxima. In contrast, the current landscape is dominated by forest. 5. Synthesis and applications. We quantified the trade-off between two potential aspects of a landscape's conservation value for

  6. The potential of mesenchymal stem cells in the management of radiation enteropathy

    PubMed Central

    Chang, P-Y; Qu, Y-Q; Wang, J; Dong, L-H

    2015-01-01

    Although radiotherapy is effective in managing abdominal and pelvic malignant tumors, radiation enteropathy is still unavoidable. This disease severely affects the quality of life of cancer patients due to some refractory lesions, such as intestinal ischemia, mucositis, ulcer, necrosis or even perforation. Current drugs or prevailing therapies are committed to alleviating the symptoms induced by above lesions. But the efficacies achieved by these interventions are still not satisfactory, because the milieus for tissue regeneration are not distinctly improved. In recent years, regenerative therapy for radiation enteropathy by using mesenchymal stem cells is of public interests. Relevant results of preclinical and clinical studies suggest that this regenerative therapy will become an attractive tool in managing radiation enteropathy, because mesenchymal stem cells exhibit their pro-regenerative potentials for healing the injuries in both epithelium and endothelium, minimizing inflammation and protecting irradiated intestine against fibrogenesis through activating intrinsic repair actions. In spite of these encouraging results, whether mesenchymal stem cells promote tumor growth is still an issue of debate. On this basis, we will discuss the advances in anticancer therapy by using mesenchymal stem cells in this review after analyzing the pathogenesis of radiation enteropathy, introducing the advances in managing radiation enteropathy using regenerative therapy and exploring the putative actions by which mesenchymal stem cells repair intestinal injuries. At last, insights gained from the potential risks of mesenchymal stem cell-based therapy for radiation enteropathy patients may provide clinicians with an improved awareness in carrying out their studies. PMID:26247725

  7. Oral tissue changes of radiation-oncology and their management

    SciTech Connect

    Fleming, T.J. )

    1990-04-01

    The cytologic effects of radiation therapy involve all tissues and most significantly bone within the treated area. Of greatest concern is the permanence of the compromised healing and resistance to infection of the irradiated tissues. Those dental procedures that do not cause tissue trauma are considered nonrisk. Any procedure that traumatizes previously irradiated tissues can exceed the healing potential of the compromised tissue and frequently results in an uncontrollable necrosis. The adequate utilization of hyperbaric oxygen therapy has been shown to be 95% effective in preventing osteoradionecrosis in postirradiated tissues. 9 references.

  8. Assessment of DNA degradation induced by thermal and UV radiation processing: implications for quantification of genetically modified organisms.

    PubMed

    Ballari, Rajashekhar V; Martin, Asha

    2013-12-01

    DNA quality is an important parameter for the detection and quantification of genetically modified organisms (GMO's) using the polymerase chain reaction (PCR). Food processing leads to degradation of DNA, which may impair GMO detection and quantification. This study evaluated the effect of various processing treatments such as heating, baking, microwaving, autoclaving and ultraviolet (UV) irradiation on the relative transgenic content of MON 810 maize using pRSETMON-02, a dual target plasmid as a model system. Amongst all the processing treatments examined, autoclaving and UV irradiation resulted in the least recovery of the transgenic (CaMV 35S promoter) and taxon-specific (zein) target DNA sequences. Although a profound impact on DNA degradation was seen during the processing, DNA could still be reliably quantified by Real-time PCR. The measured mean DNA copy number ratios of the processed samples were in agreement with the expected values. Our study confirms the premise that the final analytical value assigned to a particular sample is independent of the degree of DNA degradation since the transgenic and the taxon-specific target sequences possessing approximately similar lengths degrade in parallel. The results of our study demonstrate that food processing does not alter the relative quantification of the transgenic content provided the quantitative assays target shorter amplicons and the difference in the amplicon size between the transgenic and taxon-specific genes is minimal. PMID:23870938

  9. Radiation Effects on Emerging Technologies: Implications of Space Weather Risk Management

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Barth, Janet L.

    2000-01-01

    As NASA and its space partners endeavor to develop a network of satellites capable of supporting humankind's needs for advanced space weather prediction and understanding, one of the key challenges is to design a space system to operate in the natural space radiation environment In this paper, we present a description of the natural space radiation environment, the effects of interest to electronic or photonic systems, and a sample of emerging technologies and their specific issues. We conclude with a discussion of operations in the space radiation hazard and considerations for risk management.

  10. Contemporary management of stage i testicular seminoma: a survey of Canadian radiation oncologists

    PubMed Central

    Samant, R.; Alomary, I.; Genest, P.; Eapen, L.

    2008-01-01

    Recently published studies clearly indicate that there are now several acceptable options for managing stage i testicular seminoma patients after orchiectomy. We therefore decided to survey Canadian radiation oncologists to determine how they currently manage such patients and to compare the results with previous surveys. Our results demonstrate that adjuvant single-agent chemotherapy is being considered as an option by an increasing proportion of radiation oncologists (although it is not considered the preferred option), the routine use of radiotherapy is declining, and surveillance is becoming increasingly popular and is recommended most often. PMID:18769613

  11. Complementary Strategies for the Management of Radiation Therapy Side Effects

    PubMed Central

    Stubbe, Christine E.; Valero, Meighan

    2013-01-01

    Patients with cancer utilize complementary and alternative medicine (CAM) for a variety of purposes, one of which is the reduction of side effects of conventional treatment. With a large number of their patients using CAM, it is important for advanced practitioners in oncology to have an understanding of these therapies to better guide their patients. Side effects of radiation therapy that may have dose-limiting poten­tial include diarrhea, mucositis, skin toxicity, and xerostomia. A com­mon side effect that is not necessarily dose-limiting but considerably troublesome to patients is cancer- and treatment-related fatigue. The CAM therapies that may alleviate some of the side effects of radiation therapy include probiotics, psyllium, exercise, melatonin, honey, acu­puncture, and calendula. Therapies that require more research or have been shown to be ineffective include aloe vera, glutamine, and deglyc­yrrhizinated licorice. This article provides an overview of these thera­pies as well as related research and analysis. PMID:25032003

  12. Radiation detection and situation management by distributed sensor networks

    SciTech Connect

    Jan, Frigo; Mielke, Angela; Cai, D Michael

    2009-01-01

    Detection of radioactive materials in an urban environment usually requires large, portal-monitor-style radiation detectors. However, this may not be a practical solution in many transport scenarios. Alternatively, a distributed sensor network (DSN) could complement portal-style detection of radiological materials through the implementation of arrays of low cost, small heterogeneous sensors with the ability to detect the presence of radioactive materials in a moving vehicle over a specific region. In this paper, we report on the use of a heterogeneous, wireless, distributed sensor network for traffic monitoring in a field demonstration. Through wireless communications, the energy spectra from different radiation detectors are combined to improve the detection confidence. In addition, the DSN exploits other sensor technologies and algorithms to provide additional information about the vehicle, such as its speed, location, class (e.g. car, truck), and license plate number. The sensors are in-situ and data is processed in real-time at each node. Relevant information from each node is sent to a base station computer which is used to assess the movement of radioactive materials.

  13. Complementary strategies for the management of radiation therapy side effects.

    PubMed

    Stubbe, Christine E; Valero, Meighan

    2013-07-01

    Patients with cancer utilize complementary and alternative medicine (CAM) for a variety of purposes, one of which is the reduction of side effects of conventional treatment. With a large number of their patients using CAM, it is important for advanced practitioners in oncology to have an understanding of these therapies to better guide their patients. Side effects of radiation therapy that may have dose-limiting poten-tial include diarrhea, mucositis, skin toxicity, and xerostomia. A com-mon side effect that is not necessarily dose-limiting but considerably troublesome to patients is cancer- and treatment-related fatigue. The CAM therapies that may alleviate some of the side effects of radiation therapy include probiotics, psyllium, exercise, melatonin, honey, acu-puncture, and calendula. Therapies that require more research or have been shown to be ineffective include aloe vera, glutamine, and deglyc-yrrhizinated licorice. This article provides an overview of these thera-pies as well as related research and analysis. PMID:25032003

  14. Radiation exposure case management after incorporation of radionuclides.

    PubMed

    Goulko, Guennadi; Dörr, Harald; Meineke, Viktor

    2014-06-01

    The release of radioactive material due to accidents or terroristic actions can result in radioactive contamination of the environment and may lead to intake and incorporation of radionuclides with the consequence of prolonged radiation exposure. In this case, a decision about countermeasures must be carried out as soon as possible to reduce the resulting radiation dose. In order to be prepared for such a scenario, an Assessment and Documentation System has been developed to support the rapid assessment of internal exposures and to assist in decision making. Radionuclide distributions, excretion rates, and resulting exposures have been calculated on the basis of a reference scenario. The documentation of the results in the form of tables and graphs allows the easy and quick interpretation of measurements in terms of exposure and intake. The system in its present status gives information about possibilities of countermeasures; it is the intention of the next steps of development to give advice on the basis of estimated avertable doses. PMID:24776897

  15. Developing a decision support tool for landscape planning and management to minimize land and water degradation in Volta basin

    NASA Astrophysics Data System (ADS)

    Vlek, Lulseged Tamene, Quang Bao Le, Jens Liebe, Paul L. G.

    2009-04-01

    Although many soil/water-landscape studies have been published in the last two decades, progress in developing operational tools for supporting landscape planning to minimize land and water degradation in developing regions is still modest. Some of the existing tools are very data demanding and/or too complicated to be useful to data scarce regions. A research group at the Center for Development Research (ZEF), University of Bonn has developed a LAndscape Management and Planning Tool (LAMPT) to facilitate land management decision making and landscape planning by optimization. Firstly, we used the Revised Universal Soil Loss Equation (RUSLE) and a Distributed Sediment Delivery Model (DSDM) in a GIS environment to estimate the spatial distribution of areas experiencing different levels of soil loss in the White Volta basin. The RUSLE is employed to map the spatial patterns of major sediment source areas based on data calibrated for the study region. As RUSLE only estimates the potential gross erosion of each grid cell, a DSDM is used to estimate the sediment delivery efficiency of each cell using flow distance and velocity along the flow path. The combined models allow a classification of sub-watersheds experiencing different levels of soil loss using a soil tolerance threshold suitable for the study areas (Burkina Faso and Ghana). The result shows that the majority of areas around north-eastern and eastern parts of the White Volta basin (mainly south-eastern Burkina Faso and upper east region of Ghana) are associated with high levels of sediment yield (over 15 t ha-1 yr-1). The main reason could be high population pressure, poor surface cover and relatively high slope of some of the areas in Ghana. On the other hand, the north-western and southern parts of the basin experience low levels of sediment yield (less than 5 t ha-1 yr-1) mainly due to their flat terrain and good surface cover that encourage sediment deposition rather than erosion. We revealed that a GIS

  16. Surgical management of vestibular schwannomas after failed radiation treatment.

    PubMed

    Nonaka, Yoichi; Fukushima, Takanori; Watanabe, Kentaro; Friedman, Allan H; Cunningham, Calhoun D; Zomorodi, Ali R

    2016-04-01

    Increasing numbers of patients with vestibular schwannoma (VS) have been treated with focused-beam stereotactic radiation treatment (SRT) including Gamma knife, CyberKnife, X-knife, Novalis, or proton beam therapy. The purpose of this study was to document the incidence of tumor regrowth or symptoms that worsened or first developed following SRT and to discuss surgical strategies for patients who have failed SRT for VS. A consecutive series of 39 patients with SRT failed VS were surgically treated. Clinical symptoms, tumor regrowth at follow-up, intraoperative findings, and surgical outcome were evaluated. There were 15 males and 24 females with a mean age of 51.8 years. Thirty-six patients (92.3 %) demonstrated steady tumor growth after SRT. Two (5.1 %) patients with slight increase of the mass underwent surgical resection because of development of unbearable facial pain. Symptoms that worsened or newly developed following SRT in this series were deafness (41 %), dizziness (35.9 %), facial numbness (25.6 %), tinnitus (20.5 %), facial nerve palsy (7.7 %), and facial pain (7.7 %). Intraoperative findings demonstrated fibrous changes of the tumor mass, cyst formation, and brownish-yellow or purple discoloration of the tumor capsule. Severe adhesions between the tumor capsule and cranial nerves, vessels, and the brainstem were observed in 69.2 %. Additionally, the facial nerve was more fragile and irritable in all cases. Gross total resection (GTR) was achieved in 33.3 % of patients, near-total resection (NTR) in 35.9 %, and subtotal resection (STR) in 30.8 % of patients. New facial nerve palsy was seen in seven patients (19.4 %) postoperatively. Our findings suggest that patients with VS who fail SRT with either tumor progression or worsening of clinical symptoms will have an increased rate of adhesions to the neurovascular structures and may have radiation-influenced neuromalacia. Salvage surgery of radiation-failed tumors is more difficult and will

  17. Reply to comment by Rainer Facius et al. on "U.S. Government shutdown degrades aviation radiation monitoring during solar radiation storm"

    NASA Astrophysics Data System (ADS)

    Tobiska, W. Kent; Gersey, Brad; Wilkins, Richard; Mertens, Chris; Atwell, William; Bailey, Justin

    2014-05-01

    The premise of this comment perpetuates an unfortunate trend among some radiation researchers to minimize potential risks to human tissue from low-radiation sources. In fact, this discussion on the risk uncertainties of low-dose radiation further illustrates the need for more measurements and a program of active monitoring, especially when solar eruptive events can substantially elevate the radiation environment. This debate also highlights the context of a bigger problem; i.e., how do we as professionals act with due diligence to take the immense body of knowledge of space weather radiation effects on human tissue and distil it into ideas that regulatory agencies can use to maximize the safety of a population at risk. The focus of our article on radiation risks due to solar energetic particle events starts with our best assessment of risks and is based on the body of scientific knowledge while, at the same time, erring on the side of public safety. The uncertainty inherent in our assessment is accepted and described with this same philosophy in mind.

  18. International Patterns of Practice in the Management of Radiation Therapy-induced Nausea and Vomiting

    SciTech Connect

    Dennis, Kristopher; Zhang Liying; Lutz, Stephen; Baardwijk, Angela van; Linden, Yvette van der; Holt, Tanya; Arnalot, Palmira Foro; Lagrange, Jean-Leon; Maranzano, Ernesto; Liu, Rico; Wong, Kam-Hung; Wong, Lea-Choung; Vassiliou, Vassilios; Corn, Benjamin W.; De Angelis, Carlo; Holden, Lori; Wong, C. Shun; Chow, Edward

    2012-09-01

    Purpose: To investigate international patterns of practice in the management of radiation therapy-induced nausea and vomiting (RINV). Methods and Materials: Oncologists prescribing radiation therapy in the United States, Canada, The Netherlands, Australia, New Zealand, Spain, Italy, France, Hong Kong, Singapore, Cyprus, and Israel completed a Web-based survey that was based on 6 radiation therapy-only clinical cases modeled after the minimal-, low-, moderate-, and high-emetic risk levels defined in the antiemetic guidelines of the American Society of Clinical Oncology and the Multinational Association of Supportive Care in Cancer. For each case, respondents estimated the risks of nausea and vomiting separately and committed to an initial management approach. Results: In total, 1022 responses were received. Risk estimates and management decisions for the minimal- and high-risk cases varied little and were in line with guideline standards, whereas those for the low- and moderate-risk cases varied greatly. The most common initial management strategies were as follows: rescue therapy for a minimal-risk case (63% of respondents), 2 low-risk cases (56% and 80%), and 1 moderate-risk case (66%); and prophylactic therapy for a second moderate-risk case (75%) and a high-risk case (95%). The serotonin (5-HT){sub 3} receptor antagonists were the most commonly recommended prophylactic agents. On multivariate analysis, factors predictive of a decision for prophylactic or rescue therapy were risk estimates of nausea and vomiting, awareness of the American Society of Clinical Oncology antiemetic guideline, and European Society for Therapeutic Radiology and Oncology membership. Conclusions: Risk estimates and management strategies for RINV varied, especially for low- and moderate-risk radiation therapy cases. Radiation therapy-induced nausea and vomiting are under-studied treatment sequelae. New observational and translational studies are needed to allow for individual patient risk

  19. Vacuum Ultraviolet (VUV) radiation-induced degradation of Fluorinated Ethylene Propylene (FEP) Teflon aboard the Long Duration Exposure Facility (LDEF)

    NASA Technical Reports Server (NTRS)

    Brinza, David E.; Stiegman, A. E.; Staszak, Paul R.; Laue, Eric G.; Liang, Ranty H.

    1992-01-01

    Examination of fluorinated ethylene propylene (FEP) copolymer specimens recovered from the Long Duration Exposure Facility (LDEF) provides evidence for degradation attributed to extended solar vacuum ultraviolet (VUV) irradiation. Scanning electron microscope (SEM) images of sheared FEP film edges reveal the presence of a highly embrittled layer on the exposed surface of specimens obtained from the trailing edge of the LDEF. Similar images obtained for leading edge and control FEP films do not exhibit evidence for such an embrittled layer. Laboratory VUV irradiation of FEP films is found to produce a damage layer similar to that witnessed in the LDEF trailing edge films. Spectroscopic analyses of irradiated films provide data to advance a photochemical mechanism for degradation.

  20. Rapid degradation of azo dye Direct Black BN by magnetic MgFe2O4-SiC under microwave radiation

    NASA Astrophysics Data System (ADS)

    Gao, Jia; Yang, Shaogui; Li, Na; Meng, Lingjun; Wang, Fei; He, Huan; Sun, Cheng

    2016-08-01

    A novel microwave (MW) catalyst, MgFe2O4 loaded on SiC (MgFe2O4-SiC), was successfully synthesized by sol-gel method, and pure MgFe2O4 was used as reference. The MgFe2O4 and MgFe2O4-SiC catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), N2 adsorption analyzer (BET specific surface area), X-ray photoelectron spectroscopy (XPS). The electromagnetic parameters of the prepared catalysts were measured by vector network analyzer. The reflection loss (RL) based on the electromagnetic parameters calculated in Matlab showed MgFe2O4-SiC attained the maximum absorbing value of 13.32 dB at 2.57 GHz, which reached extremely high RL value at low frequency range, revealing the excellent MW absorption property of MgFe2O4-SiC. MW-induced degradation of Direct Black BN (DB BN) over as-synthesized MgFe2O4-SiC indicated that degradation efficiency of DB BN (20 mg L-1) in 5 min reached 96.5%, the corresponding TOC removal was 65%, and the toxicity of DB BN after degradation by MgFe2O4-SiC obviously decreased. The good stability and applicability of MgFe2O4-SiC on the degradation process were also discovered. Moreover, the ionic chromatogram during degradation of DB BN demonstrated that the C-S, C-N and azo bonds in the DB BN molecule were destroyed gradually. MW-induced rad OH and holes could be responsible for the efficient removal involved in the system. These findings make MgFe2O4-SiC become an excellent MW absorbent as well as an effective MW catalyst with rapid degradation of DB BN. Therefore, it may be promising for MgFe2O4-SiC under MW radiation to deal with various dyestuffs and other toxic organic pollutants.

  1. Surgeons' Knowledge and Practices Regarding the Role of Radiation Therapy in Breast Cancer Management

    SciTech Connect

    Zhou, Jessica; Griffith, Kent A.; Hawley, Sarah T.; Zikmund-Fisher, Brian J.; Janz, Nancy K.; Sabel, Michael S.; Katz, Steven J.; Jagsi, Reshma

    2013-12-01

    Purpose: Population-based studies suggest underuse of radiation therapy, especially after mastectomy. Because radiation oncology is a referral-based specialty, knowledge and attitudes of upstream providers, specifically surgeons, may influence patients' decisions regarding radiation, including whether it is even considered. Therefore, we sought to evaluate surgeons' knowledge of pertinent risk information, their patterns of referral, and the correlates of surgeon knowledge and referral in specific breast cancer scenarios. Methods and Materials: We surveyed a national sample of 750 surgeons, with a 67% response rate. We analyzed responses from those who had seen at least 1 breast cancer patient in the past year (n=403), using logistic regression models to identify correlates of knowledge and appropriate referral. Results: Overall, 87% of respondents were general surgeons, and 64% saw >10 breast cancer patients in the previous year. In a scenario involving a 45-year-old undergoing lumpectomy, only 45% correctly estimated the risk of locoregional recurrence without radiation therapy, but 97% would refer to radiation oncology. In a patient with 2 of 20 nodes involved after mastectomy, 30% would neither refer to radiation oncology nor provide accurate information to make radiation decisions. In a patient with 4 of 20 nodes involved after mastectomy, 9% would not refer to radiation oncology. Fewer than half knew that the Oxford meta-analysis revealed a survival benefit from radiation therapy after lumpectomy (45%) or mastectomy (32%). Only 16% passed a 7-item knowledge test; female and more-experienced surgeons were more likely to pass. Factors significantly associated with appropriate referral to radiation oncology included breast cancer volume, tumor board participation, and knowledge. Conclusions: Many surgeons have inadequate knowledge regarding the role of radiation in breast cancer management, especially after mastectomy. Targeted educational interventions may

  2. Radiation dosimetry data management using VAX C, FMS, RMS, DCL, and Oracle

    SciTech Connect

    Voltin, M.J. Jr.; Martin, A.K.

    1991-01-01

    The External Dosimetry Badge System was developed to support the radiation protection program at Los Alamos National Laboratory. The radiation protection program is responsible for monitoring external radiation exposures to approximately 7,500 Laboratory employees, visitors and contractors each month. External radiation exposure is measured using thermoluminescent dosimeters (TLDs). The system is used to control the assembly and distribution of TLD badges. The system monitors badge return and disassembly at the end of each month, and analyzes the TLDs to determine individual radiation exposure levels. Results are reported and stored in a database designed to maintain detailed individual exposure records. The system maintains a complete history of annual summaries for external exposures. The system is user-friendly with user prompts, menus, and extensive help functions. The completely menu-driven system uses VAX C, VAX Forms Management System, VMS Record Management Services, VMS Digital Command Language, and the Oracle Relational Database Management System. Design and development issues faced, and methods and techniques used in developing the system will be described. Topics discussed include consistent user interface design approaches, considerations for using VAX/VMS programming tools versus Oracle development tools to develop and implement the application, and overall system benefits. 3 refs.

  3. Management of late radiation-induced rectal injury after treatment of carcinoma of the uterus

    SciTech Connect

    Allen-Mersh, T.G.; Wilson, E.J.; Hope-Stone, H.F.; Mann, C.V.

    1987-06-01

    Sixty-one of 1418 (4.3 per cent) patients treated with radiation for carcinoma of the uterus from 1963 to 1983 had significant radiation-induced complications of the intestine develop which required a surgical opinion considering further management. Ninety-three per cent of these complications involved the rectum. Florid proctitis resolved within two years of onset in 33 per cent of the patients who were managed conservatively while 22 per cent of the patients died of disseminated disease within the same time period. Surgical treatment was eventually necessary in 39 per cent of the patients who were initially treated conservatively for radiation induced proctitis. Rectal excision with coloanal sleeve anastomosis produced a satisfactory result in eight of 11 patients with severe radiation injury involving the rectum. The incidence of radiation-induced and malignant rectovaginal fistula were similar (1 per cent), but disease-induced symptoms tended to occur earlier after primary treatment (a median of eight months) compared with radiation-induced symptoms (a median of 16 months).

  4. Cattle-rangeland management practices and perceptions of pastoralists towards rangeland degradation in the Borana zone of southern Ethiopia.

    PubMed

    Solomon, T B; Snyman, H A; Smit, G N

    2007-03-01

    A survey was conducted in the Borana pastoral areas of southern Ethiopia to assess current livestock production systems, rangeland management practices and the perceptions of the pastoralists towards rangeland degradation. This information is considered vital to future pastoral development planning and interventions. Data were collected from a total of 20 villages that were identified from 5 peasant associations, namely Did Yabello, Moyatte, Did Harra, Dubuluk and Melbana. The average household size in the study area was 7.23. The majority of the pastoralists relied on both livestock and crop farming. The average livestock holding per household was 14 cattle, 10 goats, 6 sheep and 2 camels. Livestock holdings, with the exception of camels, has shown a declining trend over time. The two most important traditional rangeland management strategies adopted by the pastoralists included burning and mobility, but since 1974/75 burning has no longer been practised. With regard to mobility, the livestock herding falls in two categories, namely: home based and satellite herding. The former involves the herding of milking cows, calves and immature animals (<2 years) close to the encampments. The latter constitutes the herding of bulls and immatures (>2 years) further away from the encampments. Based on the pastoralists' perceptions, the major constraints on livestock production in descending order, were recurrent drought, feed and water scarcity, animal diseases, predators and communal land ownership. All the respondents considered the condition of the rangelands to have declined dramatically over time. In the past most development policies were based on equilibrium theories that opposed the communal use of the rangelands and traditional range management practices. The way in which the pastoral system affects the rangeland ecosystem functioning is contentious to this theory and the 'tragedy of the commons'. There was also a perceived problem of bush encroachment and the ban on

  5. Ovarian cancer: contribution of radiation therapy to patient management: Erskine Memorial Lecture, 1983

    SciTech Connect

    Bush, R.S.

    1984-10-01

    Ovarian cancer may be treated with radiation therapy, surgery, chemotherapy, or a combination. To evaluate the contribution of radiation therapy to patient management the cure rate must be estimated; data are presented suggesting that the 5-year survival rate provides a reasonable estimate of the cure rate. A study of patients treated since 1971 showed that stage and postoperative residuum could be used to divide patients into two subgroups, a poor prognosis group and a good prognosis group; a multifactorial grouping of patients in the good prognosis group who were treated postoperatively with radiation therapy only was further able to divide patients into low-risk, intermediate-risk, and high-risk groups. Studies of radiation therapy for different subgroups are discussed; abdominopelvic irradiation has been shown to improve survival for approximately one-third of patients with cancer of the ovary.

  6. Management of Pediatric Myxopapillary Ependymoma: The Role of Adjuvant Radiation

    SciTech Connect

    Agbahiwe, Harold C.; Wharam, Moody; Batra, Sachin; Cohen, Kenneth; Terezakis, Stephanie A.

    2013-02-01

    Introduction: Myxopapillary ependymoma (MPE) is a rare tumor in children. The primary treatment is gross total resection (GTR), with no clearly defined role for adjuvant radiation therapy (RT). Published reports, however, suggest that children with MPE present with a more aggressive disease course. The goal of this study was to assess the role of adjuvant RT in pediatric patients with MPE. Methods: Sixteen patients with MPE seen at Johns Hopkins Hospital (JHH) between November 1984 and December 2010 were retrospectively reviewed. Fifteen of the patients were evaluable with a mean age of 16.8 years (range, 12-21 years). Kaplan-Meier curves and descriptive statistics were used for analysis. Results: All patients received surgery as the initial treatment modality. Surgery consisted of either a GTR or a subtotal resection (STR). The median dose of adjuvant RT was 50.4 Gy (range, 45-54 Gy). All patients receiving RT were treated at the involved site. After a median follow-up of 7.2 years (range, 0.75-26.4 years), all patients were alive with stable disease. Local control at 5 and 10 years was 62.5% and 30%, respectively, for surgery alone versus 100% at both time points for surgery and adjuvant RT. Fifty percent of the patients receiving surgery alone had local failure. All patients receiving STR alone had local failure compared to 33% of patients receiving GTR alone. One patient in the surgery and adjuvant RT group developed a distant site of recurrence 1 year from diagnosis. No late toxicity was reported at last follow-up, and neurologic symptoms either improved or remained stable following surgery with or without RT. Conclusions: Adjuvant RT improved local control compared to surgery alone and should be considered after surgical resection in pediatric patients with MPE.

  7. Management of pediatric radiation dose using GE fluoroscopic equipment.

    PubMed

    Belanger, Barry; Boudry, John

    2006-09-01

    In this article, we present GE Healthcare's design philosophy and implementation of X-ray imaging systems with dose management for pediatric patients, as embodied in its current radiography and fluoroscopy and interventional cardiovascular X-ray product offerings. First, we present a basic framework of image quality and dose in the context of a cost-benefit trade-off, with the development of the concept of imaging dose efficiency. A set of key metrics of image quality and dose efficiency is presented, including X-ray source efficiency, detector quantum efficiency (DQE), detector dynamic range, and temporal response, with an explanation of the clinical relevance of each. Second, we present design methods for automatically selecting optimal X-ray technique parameters (kVp, mA, pulse width, and spectral filtration) in real time for various clinical applications. These methods are based on an optimization scheme where patient skin dose is minimized for a target desired image contrast-to-noise ratio. Operator display of skin dose and Dose-Area Product (DAP) is covered, as well. Third, system controls and predefined protocols available to the operator are explained in the context of dose management and the need to meet varying clinical procedure imaging demands. For example, fluoroscopic dose rate is adjustable over a range of 20:1 to adapt to different procedure requirements. Fourth, we discuss the impact of image processing techniques upon dose minimization. In particular, two such techniques, dynamic range compression through adaptive multiband spectral filtering and fluoroscopic noise reduction, are explored in some detail. Fifth, we review a list of system dose-reduction features, including automatic spectral filtration, virtual collimation, variable-rate pulsed fluoroscopic, grid and no-grid techniques, and fluoroscopic loop replay with store. In addition, we describe a new feature that automatically minimizes the patient-to-detector distance, along with an

  8. Spectroscopic studies of the origin of radiation-induced degradation in phosphorus-doped optical fibers and preforms

    SciTech Connect

    Origlio, G.; Messina, F.; Cannas, M.; Girard, S.; Boukenter, A.; Ouerdane, Y.

    2010-12-15

    In this paper, we study the radiation-induced point defects related to the phosphorus element that is commonly used to improve the optical properties of silica-based glasses but is responsible of a dramatic increase in their radiation sensitivity. To this aim, the influence of x-ray irradiation on prototype phosphorus-doped canonical fibers and their related preforms was investigated by in situ radiation induced attenuation (RIA), optical absorption, and electron spin resonance (ESR) spectroscopy. The RIA spectra in the (1.5-5 eV) range, can be explained by the presence of at least three absorption bands induced by radiation exposure. Additionally the X-dose dependence of such bands was studied. The main responsible defect for these absorption peaks was the phosphorus oxygen hole center (POHC) center, whose presence was also detected by ESR measurements both in irradiated fibers and preforms, together with the lineshape of the so called P2 defect. Correlations between the RIA bands and the ESR results allow us to assign the 2.3 and 3.0 eV bands to POHCs and to propose a scheme for the simultaneous creation of POHC and P2 defects after x-ray exposure.

  9. Kinetics of ethyl paraben degradation by simulated solar radiation in the presence of N-doped TiO2 catalysts.

    PubMed

    Petala, Athanasia; Frontistis, Zacharias; Antonopoulou, Maria; Konstantinou, Ioannis; Kondarides, Dimitris I; Mantzavinos, Dionissios

    2015-09-15

    Ethyl paraben (EP), an emerging micro-pollutant representative of the parabens family, has been subject to photocatalytic degradation under simulated solar radiation at a photon flux of 1.3·10(-4) E/(m(2) s). Six nitrogen-doped titania catalysts synthesized by annealing a sol-gel derived TiO2 powder under ammonia flow and their un-doped counterparts, calcined in air at different temperatures in the range 450-800 °C, were compared under solar and visible light and the most active one (N-doped TiO2 calcined at 600 °C) was used for further tests. Experiments were performed at EP concentrations between 150 and 900 μg/L, catalyst loadings between 100 and 1000 mg/L, pH between 3 and 9, different matrices (ultrapure water, water spiked with humic acids or bicarbonates, drinking water and secondary treated wastewater) and hydrogen peroxide between 10 and 100 mg/L. For EP concentrations up to 300 μg/L, the degradation rate can be approached by first order kinetics but then shifts to lower order as the concentration increases. The rate increases linearly with catalyst loading up to 750 mg/L and hydrogen peroxide up to 100 mg/L. Near-neutral (pH = 6.5-7.5) and alkaline conditions (pH = 9) do not affect degradation, which is reduced at acidic pH. The presence of humic acids at 10-20 mg/L impedes degradation due to the competition with EP for the oxidizing species and this is more pronounced in actual wastewater matrices. UPLC-ESI-HRMS and HPLC-DAD were employed to follow EP concentration changes, as well as identify and quantify transformation by-products during the early stages of the reaction. Five such products were successfully detected and, based on their concentration-time profiles, a reaction network for the degradation of EP is proposed. Hydroxyl radical reactions appear to prevail during the initial steps as evidenced by the rapid formation of hydroxylated and dealkylated intermediates. PMID:26057263

  10. Evidence for Degradation of the Chrome Yellows in Van Gogh's Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron-Radiation-Based X-ray Techniques.

    PubMed

    Monico, Letizia; Janssens, Koen; Hendriks, Ella; Vanmeert, Frederik; Van der Snickt, Geert; Cotte, Marine; Falkenberg, Gerald; Brunetti, Brunetto Giovanni; Miliani, Costanza

    2015-11-16

    This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron-radiation-based X-ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur-rich PbCr1-x Sx O4 (x≈0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr(III) compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future. PMID:26482035